Starting from santonin,the total syntheses of cytotoxic monomeric,dimeric and trimeric quainolides dehydrozalu...
Yong Qin West China School of Pharmacy,Sichuan University,Chengdu 610041 P.R.China Innovative Drug Research Centre,Chongqing University,Chongqing 401331,P.R.China
Starting from the oxygenated piperidine building block 20,two synthetic approaches to new building blocks (8R,8aS)-and (8R,8aR)-8-hydroxy-5-indolizidinones 19a/19b and 15a/15b have been developed,respectively. The first one is based on the trans-diastereoselective reductive alkylation (dr = 93:7),followed by a four-step procedure; and the second one called for the RCM reaction on the N,O-acetal derived from a vinylation,which was followed by a pyrrole formation,and a stereocontrolled cis-selective (dr = 91:9) catalytic hydrogenation. Reduction of the diastereomer 15a produced (8R,8aR)-8-indolizidinol (18).
＜正＞The oxidative Heck reaction via direct C-H activation has gain tremendous interests during the past decades...
Peng Li~1,Gang Zhao~*,Shizheng Zhu~* Key Laboratory of Organofluorine Chemistry,Shanghai Institute of Organic Chemistry,The Chinese Academy of Sciences,345Lingling Road,Shanghai 200032,P.R.China
