Synthesis of Polyhydroxylated Pyrrolizidine Alkaloids of the Alexine Family by Tandem Ring-Closing Metathesis−Transannular Cyclization. (+)-Australine
作者:James D. White、Peter Hrnciar
DOI:10.1021/jo0012748
日期:2000.12.1
9 via oxazolidinones 15 and 51, respectively, underwent ring-closingmetathesis with Grubbs's catalyst to give azacyclooctenes 26 and 55. Treatment of each azacyclooctene with m-chloroperoxybenzoic acid afforded beta-epoxide 28 from 26 and alpha-epoxide 61 from 60. Basic hydrolysis of each of these oxazolidinones was accompanied by transannular attack at the epoxide by nitrogen, resulting in 2-(O-b