DIRECTED HOMOGENEOUS HYDROGENATION
DIRECTED HOMOGENEOUS HYDROGENATION
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DOI：
10.1002/anie.198701901
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发表时间：
1987-03-01
期刊：
影响因子：
--
通讯作者：
BROWN, JM
中科院分区：
文献类型：
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作者：
BROWN, JM
在均相催化在有机化学中的应用中，立体化学控制是一个重要的问题。在这一背景下，使用阳离子Rh或Ir催化剂进行烯烃直接加氢具有很大的潜力，因为在温和的反应条件下可以获得非常高的选择性。唯一的要求是在双键附近有一个极性官能团，该双键在催化循环中保持与金属的结合，从而通过络合的限制来控制氢的立体化学过程。取代基最常见的是羟基羟基，但也可以是酯、酰胺或氨基甲酸酯基团；其他基团仍有待仔细研究。在环状化合物中，定向加氢可以导致表面选择性，极性取代基可能在双键的β-，γ-或δ-位置。在适当的化合物中，随之而来的是非环立体选择，β-或γ-取代基，还原产物的构型可以根据简单的规则进行预测。光学活性的铑配合物的应用导致了有用的动力学拆分过程。
Stereochemical control is a major concern in the application of homogeneous catalysis to organic chemistry. In this context, the directed hydrogenation of olefins employing cationic rhodium or iridium catalysts has considerable potential, for very high selectivity can be attained under mild reaction conditions. The only requirement is a polar functional group in proximity to the double‐bond which remains bound to the metal during the catalytic cycle and thereby controls the Stereochemical course of hydrogen delivery through the constraints of chelation. The substituent is most frequently a hydroxy group OH but can also be an ester, amide or carbamate group; other groups remain to be scrutinized. In cyclic compounds, directed hydrogenation can lead to face‐selectivity, and the polar substituent may be in the β‐, γ‐, or δ‐position to the double‐bond. Acyclic stereoselection ensues with β‐ or γ‐substituents in appropriate compounds, and the configuration of reduced product is predictable on the basis of simple rules. The application of optically active rhodium complexes leads to useful kinetic resolution procedures.