Cooperative Organocatalysis for the Asymmetric γ Alkylation of α-Branched Enals
作者:Giulia Bergonzini、Silvia Vera、Paolo Melchiorre
DOI:10.1002/anie.201004761
日期:2010.12.10
α Branched leads to γ: The direct and enantioselective γalkylation of α‐substituted α,β‐unsaturated aldehydes under dienamine catalysis has been achieved. A cooperative catalysis system that involves dienamine activation of α‐branched enals and chiral Brønsted acid catalysis promotes an SN1‐alkylation pathway while ensuring complete γ‐site selectivity and high stereocontrol (see scheme; Bn=benzyl)
α分支导致γ:在二烯胺催化下,实现了α-取代的α,β-不饱和醛的直接和对映选择性γ烷基化。一个合作的催化系统涉及α-支链烯类的二烯胺活化和手性布朗斯台德酸催化,可促进S N 1烷基化途径,同时确保完全的γ位选择性和高度立体控制(参见方案; Bn =苄基)。