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Paper | Regular issue | Vol 27, No. 7, 1988, pp.1709-1712
Published online, 1st January, 1970
DOI: 10.3987/COM-88-4569
Improvements in the Total Synthesis of Physostigmine: Reductive Cyclization of Oxindoles to Tricyclic Indoleninepyrrolidines with Lithium Aluminium Hydride in Tetrahysrofuran

Qian-Sheng Yu and Arnold Brossi*

*Medical Chemistry Section, Laboratory of Chemistry, NIDDK,. National Institute of Health, Bethesda, MD 20892, U.S.A.


Reductive cyclization of oxindole 2 and carbamate 5 with LAH in THF afforded the indoleninepyrrolidines 7 and 11 in high yield. The former compound is an important intermediate in our syntheeia of (-)- and (+)-physostigmine (optical isomers of 12). Menthylearbamatee 6 and 9 prepared from 4 and 7 with menthyl chloroformate could not be separated respectively on TCL by standard techniques.