NHC-Catalyzed Oxidative Cyclization Reactions of 2-Alkynylbenzaldehydes under Aerobic Conditions: Synthesis of O-Heterocycles
作者:Jong Hyub Park、Sachin V. Bhilare、So Won Youn
DOI:10.1021/ol200481u
日期:2011.5.6
An NHC-catalyzed, regio- and stereoselective oxidative cyclization of o-alkynylbenzaldehydes bearing an unactivated alkyne moiety as an internalelectrophile has been developed to afford phthalides and isocoumarins. A single organocatalytic system enabled two sequential C−O bond formations to take place in an atom economical manner via highly efficient dual activation. Molecular oxygen in air could
Simple Gold-Catalyzed Synthesis of Benzofulvenes-<i>gem</i>-Diaurated Species as “Instant Dual-Activation” Precatalysts
作者:A. Stephen K. Hashmi、Ingo Braun、Pascal Nösel、Johannes Schädlich、Marcel Wieteck、Matthias Rudolph、Frank Rominger
DOI:10.1002/anie.201109183
日期:2012.4.27
Alkyl‐substituted diynes deliver benzofulvenes in a unique gold‐catalyzed reaction. The catalytic cycle involves the formation of gold acetylides by alkynyl C–H activation, the formation of vinylidene gold(I) intermediates by dual activation, and alkyl C–H activation by the vinylidene gold(I) species. gem‐Diaurated species obtained from the catalysis reactions prove to be highly active catalysts for