Enantioselective Organo-SOMO Cascade Cycloadditions: A Rapid Approach to Molecular Complexity from Simple Aldehydes and Olefins
作者:Nathan T. Jui、Esther C. Y. Lee、David W. C. MacMillan
DOI:10.1021/ja104313x
日期:2010.7.28
radical-mediated (4 + 2) coupling reaction of aldehydes and conjugated olefins has been achieved through asymmetric SOMO-catalysis. A radical-polar crossover mechanism is proposed wherein olefin addition to a transient enamine radical cation and oxidation of the resulting radical furnishes a cation which is vulnerable to nucleophilic addition. A range of aromatic aldehydes are shown to couple with styrenes and
醛和共轭烯烃的高选择性、自由基介导的 (4 + 2) 偶联反应已通过不对称 SOMO 催化实现。提出了自由基-极性交叉机制,其中烯烃加成到瞬时烯胺自由基阳离子和所得自由基的氧化提供易于亲核加成的阳离子。一系列芳香醛显示出与苯乙烯和二烯偶联,以提供具有高化学效率、区域选择性和立体选择性的环状产物。