Zinc‐Catalyzed Dehydrogenative Cross‐Coupling of Terminal Alkynes with Aldehydes: Access to Ynones

Abstract

Because of the lackofredox ability,zinc has seldom been used as ac atalyst in dehydrogenative cross-coupling reactions.H erein, an ovel zinc-catalyzed dehydrogenative C(sp 2 )ÀH/C(sp)ÀHc ross-coupling of terminal alkynes with aldehydes was developed, and provides asimple way to access ynones from readily available materials under mild reaction conditions.Good reaction selectivity can be achieved with a1:1 ratio of terminal alkyne and aldehyde.V arious terminal alkynes and aldehydes are suitable in this transformation.

Direct dehydrogenative alkyl Heck-couplings of vinylarenes with umpolung aldehydes catalyzed by nickel

“…In contrast, alkyl-Heck-type reactions were much more challenging and rarely explored until the last decade. Pioneered by Oshima 26 and Fu's seminal works 27 , effective strategies have been developed to facilitate this alkenylations with simple alkyl halides as electrophiles [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] . Notably, two elegant palladium-catalyzed cases involving alkyl C-H activation were disclosed by the groups of Yu 45 and Sanford 46 , which employed N-arylamide or pyridine as a neighboring directing group with stoichiometric amounts of external oxidant.…”

Catalyst‐Free Three‐Component Tandem CDC Cyclization: Convenient Access to Isoindolinones from Aromatic Acid, Amides, and DMSO by a Pummerer‐Type Rearrangement

“…The CDC reactionsb etween two compounds have been extensively investigated. [3] However,i n sharp contrast, tandem multicomponent CDC reactions,w hich represent efficientand rapid alternatives to traditional stepwise syntheses, have seen considerably lessp rogress. Moreover, it is of high interest to develop efficient and practical synthetic protocolsb yt andem CDC to construct important cyclic compounds.…”