Chiral 1,4-dicarbonyl-2,3-O-isopropylidene derivatives. Rapid racemization on standing
作者:Juan B. Rodriguez
DOI:10.1016/s0040-4020(99)00007-1
日期:1999.2
1,4-Dicarbonyl-2,3-chiral derivatives are useful synthetic precursors for the preparation of carbocyclic rings but, in many cases, losses of optical purity have been reported, 1-Deoxy-3,4-O-isopropylidene-6-O-trityl-D-erythro-hexo-2,5-diulose and 1-deoxy-3,4-O-isopropylidene-6-O-(tert-butyldiphenylsilyl)-D-erythro-hexo-2,5-diulose were synthesized from D-ribono-1,4-lactone. These compounds were selected to study the epimerizability of 2,3-O-isopropylidene-1,4-dicarbonyl derivatives. It was found that both compounds smoothly epimerize and partially racemize on standing. (C) 1999 Elsevier Science Ltd. All rights reserved.