S-Methylidene agents: preparation of chiral non-racemic heterocycles
作者:David C. Forbes、Sampada V. Bettigeri、Samit A. Patrawala、Susanna C. Pischek、Michael C. Standen
DOI:10.1016/j.tet.2008.10.019
日期:2009.1
Reaction of sulfurylide with aldehyde, imine, and ketone functionality affords the desired three-membered heterocycle in excellent yield. The sulfurylide is generated in situ upon decarboxylation of carboxymethylsulfonium betaine functionality. Of the seven carboxymethylsulfonium betaine derivatives surveyed, the highest level of conversion of π-acceptor to heterocycle was obtained with the one having
硫叶立德与醛、亚胺和酮官能团的反应以优异的产率提供所需的三元杂环。在羧甲基锍甜菜碱官能团脱羧后原位生成硫叶立德。在调查的七种羧甲基锍甜菜碱衍生物中,π-受体转化为杂环的水平最高,其中含有S-甲基和S-苯基官能团与硫代乙酸酯衍生物结合。涉及羧甲基锍甜菜碱官能团脱羧的亚甲基氮丙啶化和环氧化以反应方案、转化水平和范围的优势补充了现有技术。虽然在亚胺官能团的氮丙啶化中观察到中等水平的非对映控制,但使用 Jacobsen 的 Co(II)-salen 络合物解析的四种环氧乙烷均以高产率和对映选择性获得。分离出的手性非外消旋环氧乙烷分别以 3-溴-4-甲氧基苯甲醛和 3,4,5-三甲氧基苯甲醛为原料,正式合成 chelonin B 和考布他汀。