Designing multitarget drugs have raised considerable interest due to their advantages in the treatment of complex diseases such as cancer. Their design constitutes a challenge in antitumor drug discovery. The present study reports a dual inhibition of tubulin polymerization and HDAC activity. On the basis of 1,1-diarylethylenes (isoCA-4) and belinostat, a series of hybrid molecules was successfully designed and synthesized. In particular compounds, 5f and 5h were proven to be potent inhibitors of both tubulin polymerization and HDAC8 leading to excellent antiproliferative activity.

A novel series of tubulin polymerization inhibitors, based on fluorinated derivatives of isocombretastatin A-4 was synthesized with the goal of evaluating the effect of these compounds on the proliferative activity. The introduction of fluorine atom was performed on the phenyl ring or at the linker between the two aromatic rings. The modification of isoCA-4 by introduction of difluoromethoxy group at the para-position (3i) and substitution of the two protons of the linker by two fluorine atoms (3m), produced the most active compounds in the series, with IC50 values of 0.15–2.2 nM (3i) and 0.1–2 nM (3m) respectively, against a panel of six cancer cell lines. Compounds 3i and 3m had greater antiproliferative activity in comparison with references CA-4 or isoCA-4, the presence of fluorine group leads to a significant enhancement of the antiproliferative activity. Molecular docking studies indicated that compounds 3i and 3m occupy the colchicine binding site of tubulin. Evaluation of cytotoxicity in Human noncancer cells indicated that the compounds 3i and 3m were practically ineffective in quiescent peripheral blood lymphocytes, and may have a selective antiproliferative activity against cancer cells. Analyses of cell cycle distribution, and morphological microtubules organization showed that compound 3m induced G2/M phase arrest and, dramatically disrupted the microtubule network.

The synthesis and evaluation of a new series of IsoCombretaQuinolines (IsoCoQuines) 2 with a 2-substituted-quinoline in place of the 3,4,5-trimethoxyphenyl ring present in isoCA-4 and CA-4 are described. Most of these compounds displayed a potent cytotoxic activity (IC50 < 10 nM) against a panel of five human cancer cell lines and inhibited tubulin assembly at a micromolar level. The most potent analogue 2b, having a 3-hydroxy-4-methoxyphenyl as B-ring, led to cell cycle arrest in G2/M phase. Docking studies indicate that 2b showed a binding mode comparable to those previously observed with quinazoline analogous (IsoCoQ) and with isoCA-4 at the colchicine binding site of tubulin.

Plasminogen activator inhibitor-1 (PAI-1) is the main inhibitor of the tissue type and urokinase type plasminogen activators. High levels of PAI-1 are correlated with an increased risk of thrombotic events and several other pathologies. Despite several compounds with in vitro activity being developed, none of them are currently in clinical use. In this study, we evaluated a novel PAI-1 inhibitor, annonacinone, a natural product from the Annonaceous acetogenins group. Annonacinone was identified in a chromogenic screening assay and was more potent than tiplaxtinin. Annonacinone showed high potency ex vivo on thromboelastography and was able to potentiate the thrombolytic effect of tPA in vivo in a murine model. SDS-PAGE showed that annonacinone inhibited formation of PAI-1/tPA complex via enhancement of the substrate pathway. Mutagenesis and molecular dynamics allowed us to identify annonacinone binding site close to helix D and E and β-sheets 2A.

We report here the synthesis, the biological evaluation and the molecular modeling studies of new imidazo[1,2-a]pyridines derivatives designed as potent kinase inhibitors. This collection was obtained from 2-aminopyridines and 2-bromoacetophenone which afforded final compound in only one step. The bioactivity of this family of new compounds was tested using protein kinase and ATP competition assays. The structure-activity relationship (SAR) revealed that six compounds inhibit DYRK1A and CLK1 at a micromolar range. Docking studies provided possible explanations that correlate with the SAR data. The most active compound 4c inhibits CLK1 (IC50 of 0.7 μM) and DYRK1A (IC50 of 2.6 μM).

Breast cancer is a hormone-dependent disease in which estrogen signaling targeting drugs fail in about 10 % due to resistance. Strong evidences highlighted the mitogen role of progesterone, its ligands, and the corresponding progesterone receptor (PR) isoforms in mammary carcinoma. Several PR antagonists have been synthesized ; however, some of them are non-selective and led to side or toxic effects. Herein, we evaluated the anti-tumor activity of a commercially available PR modulator, ulipristal acetate (UPA), and a new selective and passive PR antagonist “APR19” in a novel preclinical approach based on patient-derived breast tumor (HBCx-34) xenografted in nude mice. As opposed to P4 that slightly reduces tumor volume, UPA and APR19 treatment for 42 days led to a significant 30 % reduction in tumor weight, accompanied by a significant 40 % retardation in tumor growth upon UPA exposure while a 1.5-fold increase in necrotic areas was observed in APR19-treated tumors. Interestingly, PR expression was upregulated by a 2.5-fold factor in UPA-treated tumors while APR19 significantly reduced expression of both PR and estrogen receptor α, indicating a potential distinct molecular mechanism among PR antagonists. Cell proliferation was clearly reduced in UPA group compared to vehicle conditions, as revealed by the significant reduction in Ki-67, Cyclin D1, and proliferating cell nuclear antigen (PCNA) expression. Likewise, an increase in activated, cleaved poly(ADP-ribose) polymerase (PARP) expression was also demonstrated upon UPA exposure. Collectively, our findings provide direct in vivo evidence for anti-progestin-mediated control of human breast cancer growth, given their anti-proliferative and pro-apoptotic activities, supporting a potential role in breast cancer therapy.

Potent anticancer 4-arylchromene agents 6, as restricted isoCA-4 analogues, were prepared with excellent yields by a rapid and versatile synthetic pathway. First, in the presence of PTSA in EtOH, a variety of arylalkynols 9 were transformed into substituted 4-chromanones 10 in a one pot procedure which include regioselective arylalkynols hydration, alcohol etherification, MOM-cleavage, and cyclization. Further palladium coupling reactions, using aryl halides and N-tosylhydrazones 11 gave access to a small library of functionalized 4-arylchromenes 6 with good yields. From this series of 4-arylchromenes, we have identified compound 6s which inhibit tubulin assembly at a micromolar level and demonstrate a remarkable nanomolar level of cytotoxicity against four human cancer cell lines. Docking studies showed that isoCA-4 and its restricted chromene analogue 6s adopt a similar positioning in the colchicine binding-site of tubulin.

Drug delivery of combined cytotoxic and antivascular chemotherapies in multidrug nanoassemblies may represent an attractive way to improve the treatment of experimental cancers. Here we made the proof of concept of this approach on the experimental LS174-T human colon carcinoma xenograft nude mice model. Briefly, we have nanoprecipitated the anticancer compound gemcitabine conjugated with squalene (SQ-gem) together with isocombretastatin A-4 (isoCA-4), a new isomer of the antivascular combretastatin A-4 (CA-4). It was found that these molecules spontaneously self-assembled as stable nanoparticles (SQ-gem/isoCA-4 NAs) of ca. 142 nm in a surfactant-free aqueous solution. Cell culture viability tests and apoptosis assays showed that SQ-gem/isoCA-4 NAs displayed comparable antiproliferative and cytotoxic effects than those of the native gemcitabine or the mixtures of free gemcitabine with isoCA-4. Surprisingly, it was observed by confocal microscopy that the nanocomposites made of SQ-gem/isoCA-4 distributed intracellularly as intact nanoparticles whereas the SQ-gem nanoparticles remained localized onto the cell membrane. When used to deliver these combined chemotherapeutics to human colon cancer model, SQ-gem/isoCA-4 nanocomposites induced complete tumor regression (by 93%) and were found superior to all the other treatments, whereas the overall tolerance was better than the free drug treatments. This approach could be applied to other pairs of squalenoylated nanoassemblies with other non-water-soluble drugs, thus broadening the application of the “squalenoylation” concept in oncology.

Defects in apoptosis are frequently the cause of cancer emergence, as well as cellular resistance to chemotherapy. These phenotypes may be due to mutations of the tumor suppressor TP53 gene. In this study, we examined the effect of various mitotic spindle poisons, including the new isocombretastatin derivative isoNH2CA-4 (a tubulin-destabilizing molecule, considered to bind to the colchicine site by analogy with combretastatin A-4), on BL (Burkitt lymphoma) cells. We found that resistance to spindle poison-induced apoptosis could be reverted in tumor protein p53 (TP53)-mutated cells by EBV (Epstein Barr virus) infection. This reversion was due to restoration of the intrinsic apoptotic pathway, as assessed by relocation of the pro-apoptotic molecule Bax to mitochondria, loss of mitochondrial integrity and activation of the caspase cascade with PARP (poly ADP ribose polymerase) cleavage. EBV sensitized TP53-mutated BL cells to all spindle poisons tested, including vincristine and taxol, an effect that was systematically downmodulated by pretreatment of cells with inhibitors of p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinases. Exogenous activation of p38 and JNK pathways by dihydrosphingosine reverted resistance of TP53-mutated BL cells to spindle poisons. Dihydrosphingosine treatment of TP53-deficient Jurkat and K562 cell lines was also able to induce cell death. We conclude that activation of p38 and JNK pathways may revert resistance of TP53-mutated cells to spindle poisons. This opens new perspectives for developing alternative therapeutic strategies when the TP53 gene is inactivated.

We have synthesized a large variety of CA-4 analogues having a non-isomerizable C-linker between the A-and B-aromatic rings. Most of them displayed a nanomolar level of cytotoxicity against a panel of human cancer cell lines and inhibited tubulin polymerization at a micromolar level. Among all these compounds, the most interesting compounds were undoubtedly isoCA-4 and structural analogues 18-20 as well as benzil derivatives 11 which displayed a comparable level of activity than that of CA-4. Moreover, it has been demonstrated that these drugs arrested cancer cells in the G(2)/M phase of cellular cycle and induced apoptosis at very low concentrations. In vitro antivascular effects and the binding mode of the most active compounds was also investigated.

The synthesis and structure–activity relationships associated with a series of 1,1-diarylethylene tubulin polymerization inhibitors 3 and 4 are described. The key step for their preparation involves a palladium-catalyzed coupling of N-arylsulfonylhydrazones with aryl halides, thus providing flexible and convergent access to tri- and tetrasubstituted 1,1-diarylolefins 3 and 4 related to isocombretastatin A-4 (isoCA-4). These compounds have been evaluated for tubulin polymerization inhibitory activity as well as for cytotoxic activity. The most potent compounds are 1,1-diaryl-2-methoxyethylenes 4b, 4d and 4^e having a trisubstituted double bond. They exhibited good antiproliferative activity against various human cancer cell lines (GI50 = 8–80 nM). Compounds 4b and 4^e strongly inhibited tubulin polymerization with IC50 values of 2 and 3 μM, respectively, and induced cell cycle arrest in the G2/M phase in the K562 cell line. Docking studies in the colchicine binding site of tubulin allowed identification of residues most likely to interact with these inhibitors and explain their potent anti-tubulin activity.

Currently available progesterone receptor (PR) antagonists, such as mifepristone (RU486), lack specificity and display partial agonist properties, leading to potential drawbacks in their clinical use. Recent X-ray crystallographic studies have identified key contacts involved in the binding of agonists and antagonists with PR opening the way for a new rational strategy for inactivating PR. We report here the synthesis and characterization of a novel class of PR antagonists designed from such studies. The lead molecule, the homosteroid APR19, displays in vivo endometrial antiprogesterone activity. APR19 inhibits progesterone-induced PR recruitment and transactivation from synthetic and endogenous gene promoters. Importantly, it exhibits high PR selectivity with respect to other steroid hormone receptors, and is devoid of any partial agonist activity on PR target gene transcription. Two-hybrid and immunostaining experiments reveal that APR19-bound PR is unable to interact with either transcriptional coactivators (SRC1, SCR2) or corepressors (NCoR, SMRT), in contrast to RU486-PR complexes. APR19 also inhibits agonist-induced phosphorylation of serine 294 regulating PR transcriptional activity and turnover kinetics. In-silico docking studies based on the crystal structure of the PR ligand-binding domain show that, in contrast to progesterone, APR19 does not establish stabilizing hydrogen bonds with the ligand binding cavity, resulting in an unstable ligand-receptor complex. Altogether, these properties highly distinguish APR19 from RU486 and likely its derivatives, suggesting that it belongs to a new class of pure antiprogestins which inactivate PR by a passive mechanism. These specific PR antagonists open new perspectives for long term hormonal therapy.

A series of novel benzoxepins 6 was designed and prepared as rigid-isoCA-4 analogs according to a convergent strategy using the coupling of N-tosylhydrazones with aryl iodides under palladium catalysis. The most potent compound 6b, having the greatest resemblance to CA-4 and isoCA-4 displayed antiproliferative activity at nanomolar concentrations against various cancer cell lines and inhibited tubulin assembly at a micromolar range. In addition, benzoxepin 6b led to the arrest of HCT116, K562, H1299 and MDA-MB231 cancer cell lines in the G2/M phase of the cell cycle, and strongly induced apoptosis at low concentrations. Docking studies demonstrated that benzoxepin 6b adopt an orientation similar to that of isoCA-4 at the colchicine binding site on β-tubulin.

A novel series of dihydronaphtalene, tetrahydronaphtalene and naphtalene derivatives as restricted analogues of isoCA-4 were designed, synthesized and evaluated for their anticancer properties. High cell growth inhibition against four tumour cell lines was observed at a nanomolar level with dihydronaphtalenes 1d, e and 1h, tetrahydronaphtalene 2c and naphtalene 3c. Structure–activity relationships are also considered. These compounds exhibited a significant inhibitory activity toward tubulin polymerization (IC50 = 2–3 μM), comparable to that of isoCA-4. The effect of the lead compounds 1^e and 2c on the cancer cells tested was associated with cell cycle arrest in the G2/M phase. Docking studies reveal that these compounds showed a binding mode similar to those observed with their non-constraint isoCA-4 and isoerianin congeners.

A novel class of isocombretastatin A-4 (isoCA-4) analogues with modifications at the 3′-position of the B-ring by replacement with C-linked substituents was studied. Exploration of the structure–activity relationships of theses analogues led to the identification of several compounds that exhibit excellent antiproliferative activities in the nanomolar concentration range against H1299, MDA-MB231, HCT116, and K562 cancer cell lines ; they also inhibit tubulin polymerization with potency similar to that of isoCA-4. 1,1-Diarylethylenes 8 and 17, respectively with (E)-propen-3-ol and propyn-3-ol substituents at the 3′-position of the B-ring, proved to be the most active in this series. Both compounds led to the arrest of various cancer cell lines at the G2/M phase of the cell cycle and strongly induced apoptosis. Docking of compounds 8 and 17 in the colchicine binding site indicated that their C3′ substituents guide the positioning of the B-ring in a manner different from that observed for isoCA-4.

The cytotoxic activity of a series of 23 new isoerianin derivatives with modifications on both the A and B rings was studied. Several compounds exhibited excellent antiproliferative activity at nanomolar concentrations against a panel of human cancer cell lines. The most cytotoxic compound, isoerianin (3), strongly inhibits tubulin polymerization in the micromolar range. Moreover, isoerianin leads to G2/M phase cell-cycle arrest in H1299 and K562 cancer cells, and strongly induces apoptosis. Isoerianin also disrupts the vessel-like structures formed by human umbilical vein endothelial cells (HUVECs) in vitro, suggesting that this compound may act as a vascular disrupting agent. It clearly appears that in this compound series, the 1,1-ethane bridge encountered in isoerianin derivatives can replace the 1,2-ethane bridge of natural erianin with no loss of activity. This reinforces the bioisosteric replacement approach in the combretastatin series previously reported by our research group.

A series of triarylolefins bearing the combretastatin A-4 and the isocombretastatin A-4 cores were synthesized and evaluated. The cooperative ortho-effect of a labile bromine atom in the regioselective hydrostannation of unsymmetrical diarylalkynes leading to stereodefined triarylolefins is presented.

We report here the synthesis and biological evaluation of a series of 37 compounds as precursors of potent antimalarial bis-thiazolium salts (T3 and T4). These prodrugs were either thioester, thiocarbonate or thiocarbamate type and were synthesized in one step by reaction of an alkaline solution of the parent drug with the appropriate activated acyl group. Structural variations affecting physicochemical properties were made in order to improve oral activity. Twenty-five of them exhibited potent antimalarial activity with IC50 lower than 7 nM against Plasmodium falciparum in vitro. Notably, 3 and 22 showed IC50 = 2.2 and 1.8 nM, respectively. After oral administration 22 was the most potent compound clearing the parasitemia in Plasmodium vinckei infected mice with a dose of 1.3 mg/kg.

Herein is reported a convergent synthesis of isocombretastatins A, a novel class of potent antitubulin agents. These compounds having a 1,1-diarylethylene scaffold constitute the simplest isomers of natural Z-combretastatins A that are easy to synthesize without need to control the Z-olefin geometry. The discovery of isoCA-4 with biological activities comparable to that of CA-4 represents a major progress in this field.

The cytotoxic activities of 23 new isocombretastatin A derivatives with modifications on the B-ring were investigated. Several compounds exhibited excellent antiproliferative activity at nanomolar concentrations against a panel of human cancer cell lines. Compounds isoFCA-4 (2 e), isoCA-4 (2 k) and isoNH2CA-4 (2 s) were the most cytotoxic, and strongly inhibited tubulin polymerization with IC50 values of 4, 2 and 1.5 μm, respectively. These derivatives were found to be 10-fold more active than phenstatin and colchicine with respect to growth inhibition but displayed similar activities as tubulin polymerization inhibitors. In addition, cell cycle arrest in the G2/M phase and subsequent apoptosis was observed in three cancer cell lines when treated with these compounds. The disruptive effect of 2 e, 2 k and 2 s on the vessel-like structures formed by human umbilical vein endothelial cells (HUVEC) suggest that these compounds may act as vascular disrupting agents. Both compounds 2 k and 2 s have the potential for further prodrug modification and development as vascular disrupting agents for treatment of solid tumors.

An efficient stereoselective synthesis of Z-stilbenes has been developed from diarylalkynes via a new hydrosilylation–protodesilylation process. The scope and limitation of this method is presented to stereoselectively prepare a wide range of (Z)-stilbenes in a one-pot way is presented. A concise application to the preparation of combretastatin A-4 (CA-4), a vascular targeting agent inhibitor of tubulin polymerisation is described.

A series of benzil derivatives related to combretastatin A-4 (CA-4) have been synthesized by oxidation of diarylalkynes promoted by PdI2 in DMSO. Using this new protocol, 14 benzils were prepared in good to excellent yields and their biological activity has been delineated. Several benzils exhibited excellent antiproliferative activity : for example, 4j and 4k bearing the greatest resemblance to CA-4 and AVE-8062, respectively, were found to inhibit cell growth at the nanomolar level (20–50 nM) on four human tumor cell lines. Flow cytometric analysis indicates that these compounds act as antimitotics and arrest the cell cycle in G2/M phase. A cell-based assay indicated that compounds 4j and 4k displayed a similar inhibition of tubulin assembly with an IC50 value similar to CA-4. These results clearly demonstrated that the Z-double bond of CA-4 can be replaced by a 1,2-diketone unit without significant loss of cytotoxicity and inhibition of tubulin assembly potency.

Three new series comprising 24 novel cationic choline analogues and consisting of mono- or bis (N or C-5-duplicated) thiazolium salts have been synthesized. Bis-thiazolium salts showed potent antimalarial activity (much superior to monothiazoliums). Among them, bis-thiazolium salts 12 and 13 exhibited IC50 values of 2.25 nM and 0.65 nM, respectively, against P. falciparum in vitro. These compounds also demonstrated good in vivo activity (ED50 ≤ 0.22 mg/kg), and low toxicity in mice infected by Plasmodium vinckei.

A new antimalarial pharmacological approach based on inhibition of the plasmodial phospholipid
metabolism has been developed. The drugs mimic choline structure and inhibit de novo phosphatidylcholine
biosynthesis. Three generations of compounds were rationally designed. Bisquaternary ammonium salts
showed powerful antimalarial activity, with IC50 in the nanomolar range. To remedy their low per os
absorption, bioisosteric analogues (bis-amidines) were designed and exhibited similar powerful activities.
Finally, the third generation compounds are bis-thiazolium salts and their non-ionic precursors : prodrugs,
which in vivo can lead to thiazolium drugs after enzymatic transformation.
The compounds are equally effective against multiresistant Plasmodium falciparum malaria. These molecules
exert a very rapid cytotoxic effect against malarial parasites in the very low nanomolar range and are active in
vivo against P. vinckei-infected mice, with ED50 lower than 0.2 mg/kg. They are able to cure highly infected
mice and, retain full activity after a single injection. They also retain full activity against P. falciparum and P.
cynomolgi in primate models with no recrudescence and at lower doses.
Compounds are accumulated in P.falciparum-infected erythrocyte, which ensures their potency and specificity.
Recently, we discovered that compounds also interact with malarial pigment enhancing the antimalarial effect.
It is quite likely that they are dual molecules, exerting their antimalarial activity via two simultaneous toxic
effects on the intracellular intraerythrocytic parasites. The current leader compounds are accessible in few steps
from commercial products. These crystalline molecules present a remarkable biological activity and low
toxicity which is promising for the development of a new antimalarial drug.

The palladium-catalyzed hydrostannation of terminal arylalkynes was achieved. The regioselectivity of the H−Sn bond addition across the triple bond was found to be controlled by an ortho substituent on the aromatic ring, whatever its electronic nature, to give exclusively α-branched vinylstannanes 2 in accordance with Markovnikov’s rule. Subsequent Stille cross-coupling reaction of 2 with a variety of aryl halides readily provided, in moderate to good yields, a family of functionalized 1,1-diarylethylenes 1.

Palladium-catalyzed hydrostannation reactions of ortho-disubstituted arylalkynes were achieved with total stereo- and regio-selectivity in THF at room temperature. The regioselectivity was found to be under the control of the ortho-substituents (ortho-directing effects, ODE) and pure α-vinylstannanes are produced in good yields and as single isomers regardless of the substituents’ nature. These hydrostannation α-products are precursors of choice for the preparation of stereo-defined triarylolefins.

A series of triarylolefins bearing the combretastatin A-4 and the isocombretastatin A-4 cores were synthesized and evaluated. The cooperative ortho-effect of a labile bromine atom in the regioselective hydrostannation of unsymmetrical diarylalkynes leading to stereodefined triarylolefins is presented.

Totally regioselective hydrosilylation of functionalized terminal arylalkynes was achieved using PtCl2 associated with the air-stable and bulky Xphos ligand with various silanes. Regardless of the electronic nature of the substituents on the aromatic ring, a single β-(E)-vinylsilane was obtained in excellent yields.

Hydrosilylation of functionalized terminal arylalkynes with a variety of silanes catalyzed by PtCl2 or PtO2 in the presence of the air-stable and bulky Xphos ligand was investigated. Regardless of the electronic nature (electron withdrawing or donating group) and the position (o, m, p) of the substituents on the aromatic ring, a single β-(E)-styrylsilanes was obtained in good to excellent yields. The regioselectivity of the H-Si bond addition was found to be governed by steric effects induced by the bulky Xphos ligand. A dramatic regioselectivity was also observed when functionalized terminal aliphatic alkynes were employed as a substrate and in these cases regioisomeric β-(E)-vinylsilanes were generated with excellent selectivity.

Palladium-catalyzed hydrostannation of substituted Z- and E-enynols is discussed and compared. The regioselectivity of the H−Sn bond addition was found to be controlled by the geometry of the double bond (Z- or syn-directing effect) rather than the nature of its substituents. Exclusively α-vinyl stannanes were obtained from Z-enynols having various substituents on the double bond regardless of their electronic, steric, or chelating natures.

The platinum-catalyzed hydrosilylation of unsymmetrical substituted arylalkynes with various hydrosilanes was investigated and the reaction selectivity of various para-substituted substrates was compared with that of their corresponding ortho-substituted derivatives. We showed that heterogeneous platinum oxide is a very efficient catalyst for such hydrosilylations and that H-Si bond addition proceeds in a stereoselective cis-fashion. The regioselectivity was found to be under the control of the ortho-substituent rather than due to the nature of the platinum catalyst. Aryl­alkynes with an ortho-substituent provided predominantly to exclusively α-selectivity, regardless of the electronic nature of the substituent. The precise contributions of steric, electronic, and coordinative factors controlling the regioselectivity of the H-Si bond addition are discussed.

The first platinum-catalyzed selective silylation of aryl halides including aryl iodides and bromides having an electron-withdrawing group is described. The reaction takes place rapidly in NMP with triethylsilane as a silicon source and sodium acetate to provide functionalized aryltriethylsilanes in moderate to good yields. Heteroaromatic halides also were found to be readily silylated with triethylsilane. The procedure is chemoselective and tolerates a wide variety of functional groups.

PtO2- and H2PtCl6-catalyzed hydrosilylation of internal aryl alkynes having a para or an ortho substituent with triethylsilane are discussed and compared. The regioselectivity of the H−Si bond addition was found to be controlled by the ortho substituent rather than the nature of the platinum catalyst. Arylalkynes with an ortho substituent, regardless of its electronic nature, directed the silyl substituent mainly to the α-position. PtO2 proved to be a versatile and powerful catalyst compared to H2PtCl6 since it prevents the alkyne reduction.

A highly efficient PtO2/PTSA catalyst system for the hydration of a wide array of alkynes was developed. This method proved to be compatible with a large range of functional groups and the ketone products were obtained in high yields. The scope of this methodology was also extended to the synthesis of 3-aryl-isochromenones, -indoles and -benzofurans.

An efficient regioselective deoxygenation of arylalkyl‐1,2‐diketones by the couple trimethylsilylchloride/sodium iodide has been reported. In all cases, the deoxygenation takes place on the carbonyl group (Cα=O) proximal to the aromatic ring in methylene chloride at room temperature in good yields, furnishing a series of variously functionalized alkylbenzylketones. A large range of functional groups were well tolerated on the ortho‐, meta‐ and para‐positions by this mild process regardless of their electronic effects, demonstrating the general character of the present methodology. The trimethylsilylchloride/sodium iodide reducing process was also successfully applied to reduce α‐ketoacid and α‐ketoester substrates.

In this review, the oxidation of diarylalkynes leading to functionalized benzils [di(het)aryl 1,2-diketones] is summarized. Some synthetic one-pot transformations of internal arylalkynes leading to the construction of heterocycles are presented.

For the first time, the combination of chlorotrimethylsilane with NaI is used as a selective reducting system toward 1,2-diketones. This combination is successfully evaluated with several unsymmetrically benzil derivatives, which are reduced in good yields and with a total α-regioselectivity at room temperature. Identification of benzoin intermediates is achieved, and a mechanistic radical process is proposed.

A metal-free procedure for the cyclization of (E)-1,4-di­arylenynes is described. The reaction is promoted by a catalytic amount of p-toluenesulfonic acid and takes place in ethanol at 160 °C under microwave irradiation to afford stereoselectively (E)-3-styrylisocoumarins in good to excellent yields.

A variety of 2-arylbenzo[b]furans are readily prepared in good to excellent yields from the cyclization of o-(1-alkynyl)anisole derivatives under mild reaction conditions using an alcoholic media, p-toluenesulfonic acid under microwave irradiation. Starting from the corresponding o-(1-alkynyl)thioanisole derivatives, this friendly and environmentally free-metal procedure has been successfully extended to the synthesis of benzo[b]thiophenes. Relative to the electronic nature of the substituents, the selectivity of the cyclization reaction from differently o,o′-substituted diarylalkynes is also discussed.

A series of functionalized 2-(1-phenylvinyl)benzofurans 2 and 2-(1-phenylvinyl)indoles 3 were prepared from 1-phenylvinyl iodides and silylated alkynes in a one-pot reaction. After a desilylation step, the Sonogashira coupling reaction between the resulting terminal alkynes and 1-phenylvinyliodide derivatives 6 gave enyne intermediates, which underwent a 5-endo-dig cyclization to afford 2-(1-phenylvinyl) heterocycles 2 and 3 in good yields. This method provides a rapid and efficient approach to build up benzoheterocycle-based isocombretastatin A-4 analogues of biological interest. From this series of compounds, the indoles 3^o and 3r inhibited tubulin assembly at a micromolar level comparable to that of isoCA-4.

Tributyltin hydride in N-methyl-2-pyrrolidinone (NMP) was used for the partial reduction of various functionalized acid chlorides at room temperature. This transition-metal-free procedure allows the synthesis of a range of (hetero)aromatic- and aliphatic aldehydes in good to excellent yields.

PdI2 in DMSO promoted the oxidation of functionalized diarylalkynes into benzil derivatives in excellent yields. This new oxidation reaction was achieved with short reaction times and low loading of palladium catalyst. This efficient catalytic process has been applied successfully to the one-pot construction of a series of nitrogen-containing heterocycles of biological interest according to a tandem oxidation–nitrogen nucleophiles condensation–cyclization.

p-Toluenesulfonic acid (PTSA) in ethanol was used as a mild acid catalyst for the annulation of various functionalized diarylalkynes under microwave irradiation. This metal-free process allowed the synthesis of a range of 3-aryl-substituted isocoumarins in good yields.

Regioselective hydration of a wide range of internal alkynes has been afforded in high to good yields by using PTSA in EtOH. The scope of the reaction of alkynes has been delineated. Arylaliphatic alkynes and diarylalkynes were regioselectively hydrated in good to excellent yields and short reaction times when the reaction was achieved under microwave irradiation. Moreover, diarylalkynes, arylenynes as well as diaryldiynes bearing a methoxy- or a thiomethyl substituent on the ortho position underwent a regioselective 5-endo-dig-cyclization to give a variety of 2-aryl- and 2-styrylbenzofuran or benzothiphene derivatives. We believe that, this new environmentally metal-free procedure combined to microwave irradiation would be in importance in the search of green laboratory-scale synthesis.

A convenient and general approach to the synthesis of 2-substituted 3-bromobenzofurans and -benzothiophenes was developed. The procedure is based on the cyclization of ortho-substituted arylalkynes in the presence of N-methylpyrrolidin-2-one hydrotribromide (MPHT) as a soft and easy-to-handle electrophilic brominating reagent. Under mild reaction conditions, MPHT promoted the bromocyclization of various enynes and diynes as well as arylalkynes to give 2-substituted 3-bromobenzofurans and -benzothiophenes in high to excellent yields. Subsequent functionalization by palladium-catalyzed coupling reactions at the C–Br bond afforded general access to 2,3-disubstituted benzofurans and benzothiophenes of biological interest.

A stereoselective, palladium-catalyzed, cross-coupling reaction between chloroenynes 4 and boronic acids was successfully developed. This procedure is general and provides desired functionalized enynes 1 in high yields. The scope and limitations of this new reaction are described.

An efficient palladium–copper-catalyzed three-component assembling of propargyl halides, aryl or heteroaryl halides, and secondary amines is described. A wide variety of tertiary propargylic amines were synthesized in good to excellent yields from easily accessible starting materials. This three-component assembling was also effective when using potassium phthalimide or di-tert-butyliminodicarbonate instead of secondary amines. Consequently, it provides a quick entry to N-protected propargylic amines suitable intermediates for the synthesis of primary and secondary propargylic amines. In a similar way, related compounds including propargylic amide, carbamate and sulfonamide derivatives were efficiently obtained. This catalytic domino three-component process has been applied successfully to the construction of functionalized 2-(aminomethyl)benzo[b]furan or indole derivatives of biological interest.