A flexible approach for the asymmetric syntheses of hyacinthacines A2, A3 and structural confirmation of hyacinthacine A3
作者:Wen-Jun Liu、Jian-Liang Ye、Pei-Qiang Huang
DOI:10.1039/b926741g
日期:——
A concise and flexible approach for the asymmetric syntheses of polyhydroxylated pyrrolizidine alkaloids hyacinthacines A2 and A3 has been developed using iterative reductive alkylation of O,O′-dibenzyltartarimide (5) as key steps. The ambiguity about the structure of synthetic hyacinthacine A3 due to the differences in the NMR data of the synthetic material (2) and the natural product (hyacinthacine A3) was eliminated jointly by comprehensive 1D and 2D-NMR studies, and by analysis of the 1H and 13C NMR spectra of a mixed synthetic product and natural hyacinthacine A3. The latter method also allowed a confirmation of the structure of the natural hyacinthacine A3, and may be useful for structural confirmation of other hydroxylated alkaloids.