据报道,钯催化的 dl-和内消旋 1,2-二乙烯基亚乙基碳酸酯的 1:1 混合物的不对称烯丙基烷基化。这是第一次,催化循环的电离和亲核加成步骤都作为对映体区分步骤,以产生高对映体过量的单一产物。反应以> 98% ee 进行以有效地从丙烯醛生成有用的手性构件。iso-cladospolide B 和 11-epi-iso-cladospolide B 的绝对和相对构型通过全合成验证,解决了文献中的明显差异。
Palladium-Catalyzed Asymmetric Allylic Alkylation of <i>meso- </i>and <i>dl</i>-1,2-Divinylethylene Carbonate
作者:Barry M. Trost、Aaron Aponick
DOI:10.1021/ja0578348
日期:2006.3.1
The palladium-catalyzedasymmetricallylicalkylation of a 1:1 mixture of dl- and meso-1,2-divinylethylene carbonate is reported. For the first time, both the ionization and nucleophilic addition steps of the catalytic cycle act as enantiodiscriminating steps to give a single product in high enantiomeric excess. The reactions proceed in >98% ee to efficiently generate useful chiral building blocks
据报道,钯催化的 dl-和内消旋 1,2-二乙烯基亚乙基碳酸酯的 1:1 混合物的不对称烯丙基烷基化。这是第一次,催化循环的电离和亲核加成步骤都作为对映体区分步骤,以产生高对映体过量的单一产物。反应以> 98% ee 进行以有效地从丙烯醛生成有用的手性构件。iso-cladospolide B 和 11-epi-iso-cladospolide B 的绝对和相对构型通过全合成验证,解决了文献中的明显差异。
A Convergent Pd-Catalyzed Asymmetric Allylic Alkylation ofdl- andmeso-Divinylethylene Carbonate: Enantioselective Synthesis of (+)-Australine Hydrochloride and Formal Synthesis of Isoaltholactone
作者:Barry M. Trost、Aaron Aponick、Benjamin N. Stanzl
DOI:10.1002/chem.200700832
日期:2007.11.26
The use of a mixture of dl- and meso-divinylethylene carbonate as an electrophile in palladium-catalyzed asymmetric allylic alkylation reactions is reported. From the diastereomeric mixture of meso and chiral racemic starting materials, a single product is obtained in high optical purity employing either oxygen or nitrogen nucleophiles. The resulting dienes have proven to be versatile synthetic intermediates