Formal syntheses of (+/-)-stemonamine and (+/-)-cephalotaxine.
A short and efficient approach to aza-quaternary pyrrolo[1,2-a]azepine 8 and aza-quaternary indolizine 23, as the crucial intermediates for syntheses of stemonamine (1a) and cephalotaxine (1b), has been developed on the basis of the key intramolecular Schmidt reaction of symmetric azido-diones 5 and 18, respectively.
Zhao
Yu-Ming
YM
State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou 730000, PR China.
Gu
Peiming
P
Zhang
Hai-Jun
HJ
Zhang
Qing-Wei
QW
Fan
Chun-An
CA
Tu
Yong-Qiang
YQ
Zhang
Fu-Min
FM