Evolution of Efficient Strategies for Enone−Alkyne and Enal−Alkyne Reductive Couplings
摘要:
Strategies for the reductive coupling of enones or enals with alkynes have been developed. The reducing agents employed include organozincs, organoboranes, organosilanes, and methanol. The latter of these strategies is simple, cost-effective, and tolerant of many functional groups. Isotopic labeling strategies have provided supporting evidence for the mechanistic proposals.
Highly Chemoselective and Stereoselective Synthesis of <i>Z</i>-Enol Silanes
作者:Ananda Herath、John Montgomery
DOI:10.1021/ja802844v
日期:2008.7.1
Three-component nickel-catalyzed couplings of enals, alkynes, and silanes have been developed as a new entry to enol silanes. The enol silane and a trisubstituted alkene are both formed with > 98:2 stereoselectively, and the reaction tolerates a broad range of functionality including aldehydes, ketones, esters, free hydroxyls, and basic secondary amines. A mechanistic pathway involving the formation of a metallacycle that possesses and eta(1) nickel O-enolate motif explains the high level of stereoselection.
Evolution of Efficient Strategies for Enone−Alkyne and Enal−Alkyne Reductive Couplings
作者:Wei Li、Ananda Herath、John Montgomery
DOI:10.1021/ja9083607
日期:2009.11.25
Strategies for the reductive coupling of enones or enals with alkynes have been developed. The reducing agents employed include organozincs, organoboranes, organosilanes, and methanol. The latter of these strategies is simple, cost-effective, and tolerant of many functional groups. Isotopic labeling strategies have provided supporting evidence for the mechanistic proposals.