PRACTICAL TOTAL SYNTHESES OF PHYSOSTIGMINES AND OF PHENSERINES - A SYNOPSIS

(+/-)-1,3-Dimethyl-3-cyanomethyl-5-methoxyoxindole (8), or (3S)-enrich ed 8 obtained by asymmetric alkylation, separated into the optically p ure enantiomers (8a) and (8b) when chromatographed on a microcrystalli ne cellulose triacetate (MCTA) column. Asymmetric alkylation of (+/-)- 1,3-dimethyl-5-tetrahydropyranyloxyoxindole (6) gave the nitrile (9) ( (3S) 66 % ee) which could not be separated on the MCTA column. Optical ly pure eseroline (17a) was obtained by recrystallization of the fumar ate salt (66 % ee) obtained from 9 after reduction with Vitride, reduc tive N-methylation, and treatment with 2N HCl.