Asymmetric Syntheses of (−)-8-<i>e</i><i>pi</i>-Swainsonine Triacetate and (+)-1,2-Di-<i>e</i><i>pi</i>-swainsonine. Carbonyl Addition Thwarted by an Unprecedented Aza-Pinacol Rearrangement
作者:Hossein Razavi、Robin Polt
DOI:10.1021/jo000527u
日期:2000.9.1
pyrrolidines 8a and 8b as advanced intermediates. Efficient protecting group manipulations converted pyrrolidines 8a and 8b to their corresponding partially protected analogues 10a and 10b, which upon Swern oxidation and diastereoselective Keck-type allylation with BF(3).Et(2)O afforded the required three-carbon homologues (10a, >20:1 de; 10b, 3.5:1 de). Use of the chelating Lewis acid MgBr(2) instead of BF(3)