Diastereodifferentiating the [2+2] Photocycloaddition of Ethylene to Arylmenthyl Cyclohexenonecarboxylates: Stacking-Driven Enhancement of the Product Diastereoselectivity That Is Correlated with the Reactant Ellipticity
作者:Ken Tsutsumi、Yuuki Yanagisawa、Akinori Furutani、Tsumoru Morimoto、Kiyomi Kakiuchi、Takehiko Wada、Tadashi Mori、Yoshihisa Inoue
DOI:10.1002/chem.201000429
日期:2010.7.5
Upon diastereodifferentiating the [2+2] photocycloaddition of ethylene to a series of p‐substituted (−)‐8‐phenylmenthyl cyclohexenonecarboxylates, the diastereoselectivity was critically controlled by the nature of the substituent introduced to the chiral auxiliary, and the p‐nitro‐substituted substrate afforded the cycloadducts in 90 % diastereomeric excess (de) and with 97 % isolated yield. Detailed
在将乙烯的[2 + 2]光环加成与一系列对位取代的(-)-8-苯基薄荷基环己烯酮羧酸酯进行非对映异构反应后,非对映异构选择性受到引入手性助剂和对硝基硝基化合物的性质的严格控制。取代的底物可提供90%非对映异构体过量(de)的环加合物,分离产率为97%。详细的实验和理论构象分析表明,芳族助剂与环己烯酮部分的堆积相互作用在确定底物构象方面起着决定性作用,因此是de的显着增强。特别令人感兴趣的,该产品取消与底物的椭圆率直接相关,使我们能够在光辐照之前“预测” de。