Asymmetric Construction of Bicyclic [3.1.0] Compounds and Its Application

点击翻译按钮获取中文摘要

Highly stereoselective syntheses of chiral bicyclic [3.1.0] compounds have been developed by several methods. On a way of this research project, some total syntheses of natural products were also achieved by a palladium-mediated biaryl coupling reaction of phenyl benzoate derivatives.1.A Reaction of σ-Symmetric Ketone CompoundsA symmetric ketone was prepared as the substrate, through the Meinwald rearrangement of norbornadiene. An enentioselective deprotonation reaction was attempted using several chiral amide bases. This reaction was quite successful to produce an optically active bicycle[3.1.0] compound with high enantioselectivity.Next, a symmetric epoxyketone was examined on the enantioselective deprotonation reaction using chiral amide bases. This reaction was also successful to generate the corresponding enolate followed by a transannular carbon-carbon bond formation accompanying an epoxy opening. The obtained product was transformed into the optically active bicyclo[3.1.0] compound with high optical purity.2.Optical Kinetic Resolution Using the Baker's YeastAn optical kinetic resolution of a racemic bicyclo[3.1.0] compound using the baker's yeast was attempted. After various examination of the reaction conditions and work-up methods, we found that this technique was effective to give the optical active bicycle[3.1.0] compound with high stereoselectivity. The optical purity and the absolute configuration were determined by comparison with a reported information.