Syntheses of Enantiomerically Pure Violaxanthins and Related Compounds

Article abstract of DOI:10.1002/hlca.19880710502

The epoxides 16 and ent-16, prepared by Sharpless-Katsuki oxidation of 15 in excellent yield and very high enantiomeric purity, were used as synthons for the preparation of (+)-(S)-didehydrovomifoliol (45), (+)-(6S,7E,9E)-abscisic ester 46, (+)-(6S,7E,9Z)-abscisic ester 47, (-)-(3S,7E,9E)-xanthoxin (49), (-)-(3R,7E,9E)-xanthoxin (50), (3S,5R,6S,3'S,5'R,6'S,all-E)-violaxanthin (1), (3R,5R,6S,3'R,5'R,6'S,all-E)-violaxanthin (55) and their (9Z) (see 53, 57), (13Z) (see 54, 58), and (15Z) (see 60) isomers.The novel violadione (61) was prepared from 1 by oxidation with DMSO/Ac2O.By base treatment, 61 was converted into violadienedione (62), a potential precursor of carotenoids with phenolic end groups.