A Divergent Synthesis of Functionalized Unsaturated δ-Lactones from α-Alkenoyl-α-carboxyl Ketene Dithioacetals
作者:Jun Liu、Mang Wang、Bing Li、Qun Liu、Yulong Zhao
DOI:10.1021/jo0702488
日期:2007.6.1
A divergent synthesis of functionalized unsaturated δ-lactones 2, 3, 4, and 5 has been developed starting from the readily available α-alkenoyl-α-carboxyl ketene dithioacetals 1 in high to excellent yields under mild reaction conditions. Thus, 6-substituted 3-(1,3-dithiolan/dithian-2-ylidene)-3H-pyran-2(6H)-ones 2, obtained from a consecutive reduction with NaBH4 and acidic workup of 1 via a novel
官能不饱和δ内酯的发散合成2,3,4,和5已经开发从容易获得的α链烯酰基-α-羧基烯酮二硫开始1在高,以温和的反应条件下具有优异的产率。因此,通过用NaBH 4连续还原和通过酸处理1的方法获得6-取代的3-(1,3-二硫杂环戊烷/二乙-2-亚烷基)-3 H-吡喃-2(6 H)-ones 2。新颖插烯Pummerer重环化,可以进一步转化成α-吡喃酮3,4,和5经三乙胺催化连续异构化(给出3),然后进行脱硫缩醛化(给出4)或用Vilsmeier试剂甲酰化(给出5)。