Synthesis of (−)-Neothiobinupharidine

An eight step, asymmetric synthesis of a dimeric thiaspirane nuphar alkaloid from 3-methyl-2-cyclo-pentenone is reported. The brevity of the route relies on a useful procedure for tandem reductive allylation of cyclopentenones, as well as the minimization of redox manipulations and other functional group interconversions. The distribution of products that arise from spontaneous dimerization points to a more complex biosynthesis.本文报道了一条以3-甲基-2-环戊烯酮为起始原料，经八步不对称合成二聚硫螺烷萍蓬草生物碱的路线。该合成路线的简洁性，依托于环戊烯酮还原烯丙基化串联反应这一实用方法，并最大限度缩减了氧化还原操作与其他官能团互变步骤。由自发二聚反应生成的产物分布特征，提示其生物合成过程可能更为复杂。