Asymmetric Hydrogenations for the Synthesis of Boc-Protected 4-Alkylprolinols and Prolines
作者:Juan R. Del Valle、Murray Goodman
DOI:10.1021/jo034214l
日期:2003.5.1
in peptides, peptidomimetics, and natural products has motivated researchers to find new and efficient routes for their preparation. Herein, we report a general approach to the synthesis of Boc-protected 4-alkylprolinols and prolines via a divergent asymmetric hydrogenation strategy. Intermediate exocyclic olefins were prepared by Wittig-type reactions with ketone 6 and subjected to hydroxyl and sterically
4-取代的脯氨醇及其相应的脯氨酸在肽,拟肽和天然产物中的用途促使研究人员寻找新的有效制备方法。在这里,我们报告了一种通过不对称加氢策略合成Boc保护的4-烷基脯氨醇和脯氨酸的一般方法。中间体外环烯烃通过与酮6的维蒂希型反应制备,并进行羟基还原和空间定向还原。事实证明,Crabtree催化剂(Ir [COD] PyPCy(3)PF(6))在非对映选择性氢化中非常有效,可得到反式取代的吡咯烷(9)。在用阮内镍进行异质氢化中也观察到了良好的面部选择性,从而获得了顺式取代的吡咯烷(11)。运用这种策略,