Palladium-catalyzed carbothiolation of terminal alkynes with azolyl sulfides affords various 2-(azolyl)alkenyl sulfides with perfect regio-and stereoselectivities. The present addition reaction proceeded through a direct cleavage of carbon-sulfur bonds in azolyl sulfides. The resulting adducts that are useful intermediates in organic synthesis are further transformed to multi-substituted olefins containing azolyl moieties.Carbothiolation of alkynes has been regarded as the most ideal approach to the highly substituted alkenyl sulfides in organic synthesis, which can generate carboncarbon and carbon-sulfur bonds simultaneously. 1 Regioand stereoselective addition of various carbon-sulfur bonds to alkynes has been achieved by using transition metal catalysts; thioesterification, 2 cyanothiolation, 3 allylthiolation, 4 alkenylthiolation, 5 acylthiolation, 6 iminothiolation, 7 alkynylthiolation, 8 and alkylthiolation. 9,10 Although only decarbonylative addition reaction of thioesters is known, 11 the atom-economical arylthiolation across alkynes has yet to be disclosed to date because carbon-sulfur bonds in aryl sulfides tend to cause a reversible oxidative addition. 12 While it was previously found that aryl sulfides underwent cross-coupling with organometallic reagents 13 probably because of the high reactivity of the once formed oxidative adducts for subsequent transmetalation, arylthiolation of alkynes is unprecedented.Recently, Weller and Willis have reported rhodiumcatalyzed addition of aryl sulfides bearing unique activating groups to terminal alkynes as a specific case. 14 On the other hand, addition reaction of heteroaryl sulfides to alkynes, which can construct the ubiquitous skeletons in pharmaceuticals and agrochemicals, 15 is significantly limited despite its utility. Although platinum-catalyzed furylthiolation, 11b,16 thienylthiolation, 17 and pyridylthiolation 18 of terminal alkynes with thioesters or with heteroaryl halides and arenethiolate salts are only known, those reactions produce toxic carbon monoxide or undesired by-products. We have recently disclosed the regioand stereocontrolled chlorothiolation of alkynes with transition metal catalysts through the chlorine-sulfur bond cleavage of sulfenyl chlorides. 19 During the course of our research on selective addition of organosulfur compounds to alkynes, we investigated carbothiolation with a direct activation of heteroaryl sulfides. Herein, we report that a palladium complex ligated with Nheterocyclic carbene (NHC) catalyzed regio-and stereoselective addition of azolyl sulfides to terminal alkynes.

This review focuses on the synthesis of 3-hydroxyisoindolinones, and their application as substrates in stereoselective catalytic transformations reported from 2010 to date. These compounds have attracted much attention among synthethic...

Formal Betti reaction between variously substituted phenols and benzophenone-derived imines to afford α-triphenylmethylamines is reported. Key to success of this transformation is the in situ generation of the reactive benzophenone iminium species under organocatalytic conditions. Different phenols reacted smoothly enabling the synthesis of an array of α-triphenylmethylamines, which are highly valued structural motifs in bioactive molecules and chemical sensors.

A three-step method based on Pd-catalyzed haloallylation of alkynes, Pd-catalyzed cross-coupling, and Ru-catalyzed ring-closing metathesis constitutes a new and short approach to variety of 1,2-substituted cyclopentadienes. The scope of the method is broad with respect to different substituents (alkyl, aryl, metallocenyl, and other substituents as well as their combinations are tolerated), and all steps proceeded with sensible yields. As a demonstration of product utility, several of the prepared cyclopentadienes were converted into the corresponding ferrocenes.

We report a study on the relationship between the polarization of C≡C bond in a series of 2‐alkynylbenzaldehydes and the regioselectivity of their Pd‐catalyzed annulation reactions. The electrophilic and nucleophilic character of the triple bond carbon atoms was examined using 13C and HMBC NMR experiments. The direction of polarization is determined only by the formyl group and its position on an aromatic ring. On the other hand, the strength of the polarization expressed through chemical shift difference Δδ of acetylenic carbon atoms is a result of electron‐withdrawing or electron‐donating ability of the other substituent. Out of two possible regioisomers, the Pd‐catalyzed cyclization reactions of 2‐alkynylbenzaldehydes that were studied predominantly afforded 1H‐isochromenes suggesting that the polarization of a triple bond is one of the contributing factors in the regioselectivity of this process.