Enantioselective Bronsted Base Catalysis with Chiral Cyclopropenimines
Enantioselective Bronsted Base Catalysis with Chiral Cyclopropenimines
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DOI：
10.1021/ja3015764
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发表时间：
2012-03-28
影响因子：
15
通讯作者：
Lambert, Tristan H.
中科院分区：
文献类型：
--
作者：
Bandar, Jeffrey S.;Lambert, Tristan H.
Cyclopropenimines are shown to be a highly effective new class of enantioselective Bronsted base catalysts. A chiral 2,3-bis(dialkylamino)cyclopropenimine catalyzes the rapid Michael reaction of a glycine imine substrate with high levels of enantioselectivity. A preparative scale reaction to deliver 25 g of product is demonstrated, and a trivial large scale synthesis of the optimal catalyst is shown. In addition, the basicity of a 2,3-bis(dialkylamino)cyclopropenimine is measured for the first time and shown to be approximately equivalent to the P-1-tBu phosphazene base. An X-ray crystal structure of the protonated catalyst is shown along with a proposed mechanistic and stereochemical rationale.
