S-亚甲基试剂：手性非外消旋杂环化合物的制备
S-Methylidene Agents: Preparation of Chiral Non-Racemic Heterocycles.
作者信息
Forbes David C, Bettigeri Sampada V, Patrawala Samit A, Pischek Susanna C, Standen Michael C
机构信息
Department of Chemistry, University of South Alabama, Mobile, AL 36688, USA.
出版信息
Tetrahedron. 2009 Jan 3;65(1):70-76. doi: 10.1016/j.tet.2008.10.019.
Reaction of sulfur ylide with aldehyde, imine, and ketone functionality affords the desired three-membered heterocycle in excellent yield. The sulfur ylide 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 having S-methyl and S-phenyl functionality bound to a thioacetate derivative. Methylene aziridinations and epoxidations involving the decarboxylation of carboxymethylsulfonium betaine functionality complements existing technologies with the advantages of the reaction protocol, levels of conversion and scope. While moderate levels of diastereocontrol were observed in the aziridination of imine functionality, the four oxiranes resolved using Jacobsen's Co(II)-salen complex were obtained in both high yield and enantioselectivity. The isolated chiral non-racemic oxiranes constitute the formal synthesis of chelonin-B and combretastatin starting from 3-bromo-4-methoxybenzaldehyde and 3,4,5-trimethoxybenzaldehyde respectively.
硫叶立德与醛、亚胺和酮官能团反应，能以优异的产率得到所需的三元杂环。硫叶立德是在羧甲基锍甜菜碱官能团脱羧时原位生成的。在所研究的七种羧甲基锍甜菜碱衍生物中，当硫甲基和硫苯基官能团与硫代乙酸酯衍生物相连时，π-受体向杂环的转化率最高。涉及羧甲基锍甜菜碱官能团脱羧的亚甲基氮杂环丙烷化和环氧化反应，以反应方案、转化率和适用范围等优势补充了现有技术。虽然在亚胺官能团的氮杂环丙烷化反应中观察到中等程度的非对映体控制，但使用雅各布森钴（II）-双水杨醛络合物拆分得到的四种环氧乙烷，产率和对映选择性都很高。分离得到的手性非外消旋环氧乙烷分别从3-溴-4-甲氧基苯甲醛和3,4,5-三甲氧基苯甲醛出发，构成了对Chelonin-B和康普他汀的形式合成。
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