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Discovery and Application of Doubly Quaternized Cinchona‐Alkaloid‐Based Phase‐Transfer Catalysts 下载免费PDF全文
Bangping Xiang Kevin M. Belyk Robert A. Reamer Nobuyoshi Yasuda 《Angewandte Chemie (International ed. in English)》2014,53(32):8375-8378
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 as low as 0.3 mol % under mild conditions. 相似文献
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