Stereocontrol in the EtAlCl<sub>2</sub>-Induced Cyclization of Chiral γ,δ-Unsaturated Methyl Ketones To Form Cyclopentanones
作者:Barry B. Snider、Mercedes Lobera、Tracy P. Marien
DOI:10.1021/jo034561v
日期:2003.8.1
EtAlCl(2)-induced cyclization of chiral gamma,delta-unsaturated ketones 11c and 17b takes place mainly from the expected face. The selectivity is modest for 11c (60:40) in which the large substituent is a primary alkyl group and the medium substituent is a methyl group and excellent for 17b (93:7) in which the large substituent is a cyclohexyl group and the medium substituent is a methyl group. The
EtAlCl(2)诱导的手性γ,δ-不饱和酮11c和17b的环化主要发生在预期的面部。对于11c(60:40)(其中大取代基是伯烷基,中等取代基是甲基),选择性适中;对于17b(93:7)(其中大取代基是环己基和中等介质),选择性很好取代基是甲基。17a的环化是异常的,这表明苯基不仅具有简单的空间效应。