Total syntheses of (.+-.)-physovenine and (.+-.)-physostigmine. An application of tandem electrocyclic-[3, 3] sigmatropic reaction of benzocyclobutenes
K Shishido, E Shitara, H Komatsu…
文献索引：Shishido; Shitara; Komatsu; et al. Journal of Organic Chemistry, 1986 , vol. 51, # 15 p. 3007 - 3011
A high yield (40% overall yield) 14step synthesis of (&)-physovenine and a formal synthesh of (&)-physostigmine, as applications of the tandem electrocyclic-[3, 3] sigmatropic reaction of benzocyclobutenes, are described. The thermolysis of the benzocyclobutenyl allyl ester 6 givea quantitatively the isochromanone 7, which can be elaborated to the key oxindole intermediate 8 in a seven-step sequence.(&)-Physovenine is obtained from 8 through a ...
