Phosphine-Catalyzed Doubly Stereoconvergent γ-Additions of Racemic Heterocycles to Racemic Allenoates: The Catalytic Enantioselective Synthesis of Protected α,α-Disubstituted α-Amino Acid Derivatives.
Phosphine-Catalyzed Doubly Stereoconvergent γ-Additions of Racemic Heterocycles to Racemic Allenoates: The Catalytic Enantioselective Synthesis of Protected α,α-Disubstituted α-Amino Acid Derivatives.
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膦催化外消旋杂环与外消旋联烯酸酯的双立体会聚γ-加成：受保护的α,α-二取代α-氨基酸衍生物的催化对映选择性合成。
DOI：
10.1021/jacs.5b05528
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发表时间：
2015-07-29
影响因子：
15
通讯作者：
Fu GC
中科院分区：
文献类型：
--
作者：
Kalek M;Fu GC
近年来，人们开发了一些方法，将亲核试剂与现成的烯丙酸盐和炔烃酸盐进行不对称γ加成，生成有用的α，β-不饱和羰基化合物，这些化合物具有很高的立体选择性，在γ或δ位置具有立体中心（但不是两者都有）。如果能有效地控制新键两端的立体化学，这种方法的实用性将大大提高。在本报告中，我们描述了这一目标的实现，具体来说，手性膦酸酯可以催化外消旋亲核试剂到外消旋亲电试剂的立体收敛γ加成；该方法通过选择合适的杂环作为亲核配合物，合成了收率高、非对映选择性和非对映选择性好的受保护α、α-二取代α-氨基酸衍生物。
Methods have recently been developed for the phosphine-catalyzed asymmetric γ-addition of nucleophiles to readily available allenoates and alkynoates to generate useful α,β-unsaturated carbonyl compounds that bear a stereogenic center in either the γ or the δ position (but not both) with high stereoselectivity. The utility of this approach would be enhanced considerably if the stereochemistry at both termini of the new bond could be controlled effectively. In this report, we describe the achievement of this objective, specifically, that a chiral phosphepine can catalyze the stereoconvergent γ-addition of a racemic nucleophile to a racemic electrophile; through the choice of an appropriate heterocycle as the nucleophilic partner, this new method enables the synthesis of protected α,α-disubstituted α-amino acid derivatives in good yield, diastereoselectivity, and enantioselectivity.