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Absolute Configurations of Goniodiol, Goniodiol Monoacetate and Other Related Dihydropyrones from Synthetic, Circular Dichroism and X-Ray Crystallographic Evidence
B TALAPATRA, A POREL, K BISWAS, S K TALAPATRA
Published in INDIAN CHEMICAL SOC
1997
Volume: 74
   
Issue: 43781
Pages: 896 - 903
Abstract
The absolute configuration of (+)-gonidiol [6-(7,8-dihydro-7,8-dihydroxystyryl)-5,6-dihydro-2-pyrone] (3) has been unambiguously and independently determined and revised as 7(R),8(R) from the circular dichroism (CD) studies of the diol and its dibenzoate. The 6(R) configuration that follows from its already reported 6,7-threo configuration is also confirmed by the CD spectrum of 3. Thus, the other congener chemically correlated natural dihydropyrans (+)-goniodiol monoacetate (2), (+)-goniodiol diacetate (1) and (+)-goniotriol (4), isolated from Goniothalamus sesquipedalis (Annonaceae) must possess the same 6(R),7(R),8(R) absolute configuration. The 5(R) configuration of (+)-goniotriol (4) is predicted from the 5,6-threo configuration, based on the J5,6-value as well as from biogenetic ground. Synthetic evidences known in the literature for the absolute configuration of goniodiol and some structurally related natural products have also been incorporated. The X-ray crystallographic structure determination of (+)-goniodiol monoacetate (2) unambiguously confirms its 6,7-threo and 7,8-erytho relationship with 6(R),7(R),8(R) configuration. The molecular conformations in solution and crystalline state have also been studied.
About the journal
JournalJournal of the Indian Chemical Society
PublisherINDIAN CHEMICAL SOC
ISSN0019-4522