Organocatalytic Asymmetric Reaction Cascade to Substituted Cyclohexylamines
作者:Jian Zhou、Benjamin List
DOI:10.1021/ja072134j
日期:2007.6.1
We report a new strategy for organocatalytic cascade reactions. Accordingly, enamine catalysis, iminium catalysis, and Bronsted acid catalysis can work in concert in a highlyenantioselective organocatalytic cascadesequence toward chiral cis-3-substituted cyclohexylamines. We found that an achiral amine in combination with a catalytic amount of a chiral Bronsted acid can accomplish an aldol additi
Phosphine Oxide-Catalyzed Enantioselective Intramolecular Aldol Reaction via Regioselective Enolization of Unsymmetrical Diketones with Tetrachlorosilane
The phosphine oxide-catalyzed asymmetric intramolecular aldol reactions of diketones were investigated. The combination of tetrachlorosilane and a chiral phosphine oxide catalyst promoted the acetyl-selective enolization of diketones, and the subsequent intramolecular aldol reaction occurred in an enantioselective manner. The introduction of two trimethylsilyl groups at the 4- and 4′-positions in BINAP