Kinetic resolution and parallel kinetic resolution of methyl (±)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives
作者:Stephen G. Davies、A. Christopher Garner、Marcus J. C. Long、Rachel M. Morrison、Paul M. Roberts、Edward D. Savory、Andrew D. Smith、Miles J. Sweet、Jonathan M. Withey
DOI:10.1039/b506339f
日期:——
anti- to the stereodirecting 5-alkyl substituent. Treatment of a range of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates with both lithium (+/-)-N-benzyl-N-alpha-methylbenzylamide and lithium (+/-)-N-3,4-dimethoxybenzyl-N-alpha-methylbenzylamide indicates significant enantiorecognition in their mutual kinetic resolutions, with preferential addition anti- to the 5-alkyl substituent, giving the 1,2-syn-1
在高底物控制水平(> 88%de)的情况下,将二苄基氨基化锂与5-异丙基,5-苯基-和5-叔丁基-环戊烯-1-羧酸甲酯共轭加成,并优先向环状表面添加抗立体定向5-烷基取代基的α,β-不饱和受体。用(+/-)-N-苄基-N-α-甲基苄基酰胺和(+/-)-N-3锂处理一系列(+/-)-5-烷基-环戊烯-1-羧酸甲酯,4-二甲氧基苄基-N-α-甲基苄基酰胺在它们的相互动力学拆分中显示出显着的对映体识别特征,并优先对5-烷基取代基进行反加,得到1,2-syn-1,5-反排列(E> 16 )在烯醇化质子化后抗氨基官能团。