Intramolecular asymmetric Pummerer reactions as a key step in the synthesis of bicyclic precursors of anthracyclinones
作者:Jose Luis Garcı́a Ruano、Cristina Garcı́a Paredes
DOI:10.1016/s0040-4039(99)02025-0
日期:2000.1
Highly stereoselective Pummerer reactions were observed on reaction of β-hydroxysulfoxides 2a–2d and 2′b with TMSOTf. Sulfenium intermediates are captured intramolecularly by the electrophilic aromatic ring, thus yielding bicyclic structures with a p-tolylsulfenyl group at the benzylic position in a cis arrangement with respect to the hydroxyl group. The stereogenicity transfer seems to be mainly controlled
高立体选择性Pummerer重反应中观察到对βhydroxysulfoxides的反应图2a - 2d中和2 ' b与将TMSOTf。intermediate中间体被亲电芳香环分子内捕获,从而产生在相对于羟基的顺式排列的苄基位置具有对甲苯磺酰基的双环结构。立体异构性转移似乎主要由羟基化的手性碳控制。所得化合物3a,3c和3d可用作不同的蒽环素的双环前体。