Discovery and Application of Doubly Quaternized Cinchona-Alkaloid-Based Phase-Transfer Catalysts
作者:Bangping Xiang、Kevin M. Belyk、Robert A. Reamer、Nobuyoshi Yasuda
DOI:10.1002/anie.201404084
日期:2014.8.4
We report the discovery of novel N,N′‐disubstituted cinchona alkaloids as efficient phase‐transfer catalysts for the assembly of stereogenic quaternary centers. In comparison to traditional cinchona‐alkaloid‐based phase‐transfer catalysts, these new catalysts afford substantial improvements in enantioselectivity and reaction rate for intramolecular spirocyclization reactions with catalyst loadings
我们报道了新型的N,N′-二取代金鸡纳生物碱的发现,该生物碱是用于组装立体成象四元中心的有效相转移催化剂。与传统的基于金鸡纳生物碱的相转移催化剂相比,这些新型催化剂在温和条件下的分子内螺环化反应中的对映选择性和反应速率有了显着提高,催化剂负载量低至0.3 mol%。