Multiply-deuterated syringolide2 3 was prepared from D-xylulose and 8-bromooctanoic acid by a convergent route based on our previously reported biomimeticsynthesis of this microbialelicitor. Key steps were the thermal acylation of the anisylidene-protected sugar 6 with the C-octenoyl Meldrum's acid derivative 7b, the one-pot triple-cyclisation of the xylulose β-ketoester 9b to 9,10-dehydrosyringolide 2 (10),
Factors controlling the biomimetic triple cyclisation of xylulose β-keto-esters to syringolides. Part 1: Synthesis of 4′-deoxysyringolide 2
作者:Simon A. Bennett、Rodney W. Rickards
DOI:10.1016/s0040-4039(03)01682-4
日期:2003.9
Treatment of the 4-deoxy-d-xylulose β-ketodecanoate 13c with basic alumina affords 4′-deoxysyringolide 2 14 as a single stereoisomer, indicating that the course of the biomimetic triple cyclisation of the corresponding d-xylulose ester 3b to syringolide2 5b is not dependent upon the presence of the 4R-hydroxyl group. The diacyl butanolide 15 is formed simultaneously by a side reaction of the initial