Unexpectedly convenient and stereoselective synthesis of 4α-acyloxy-2-chloropodophyllotoxins in the presence of BF 3 ·Et 2 O
作者:Hui Xu、Xiao Xiao、Xue-Fei Zhao、Yong Guo、Xiao-Jun Yao
DOI:10.1016/j.bmcl.2011.05.004
日期:2011.7
configuration was mainly stereocontrolled by the configuration of C-2 chlorine atom, were unexpectedly prepared by the reaction of 2-chloropodophyllotoxin with carboxylic acids in the presence of BF3·Et2O. Compared with ordinary esterifications of carboxylic acids mediated by the condensation agent, for example, N,N’-diisopropylcarbodiimide (DIC), the present method made the procedure for the preparation