Dual Visible Light Photoredox and Gold-Catalyzed Arylative Ring Expansion
摘要:
A combination of visible light photocatalysis and gold catalysis is applied to a ring expansion-oxidative arylation reaction. The reaction provides an entry into functionalized cyclic ketones from the coupling reaction of alkenyl and allenyl cycloalkanols with aryl diazonium salts. A mechanism involving generation of an electrophilic gold(III)-aryl intermediate is proposed on the basis of mechanistic studies, including time-resolved FT-IR spectroscopy.
Gold(I)-Catalyzed Enantioselective Ring Expansion of Allenylcyclopropanols
作者:Florian Kleinbeck、F. Dean Toste
DOI:10.1021/ja904055z
日期:2009.7.8
The asymmetric gold(I)-catalyzedring expansion of 1-allenylcyclopropanols is described. The method provides synthetically valuable cyclobutanones with a vinyl-substituted quaternary stereogenic center in high enantioselectivities and yields. The method shows a broad substrate scope, tolerating protected alcohols and amines, alkenes, unsaturated esters, and acetals. The reaction is easily adjustable