Development of N,N-bis(perfluoroalkanesulfonyl)squaramides as new strong Brønsted acids and their application to organic reactions
作者:Cheol Hong Cheon、Hisashi Yamamoto
DOI:10.1016/j.tet.2010.03.120
日期:2010.6
l groups have been developed and applied to several organic reactions. These squaramides are bench-stable and exhibit much higher reactivities in several organic reactions than squaric acid itself. N,N-Bis(trifluoromethanesulfonyl)squaramide 2a was applied to the Mukaiyama aldol reaction and Mukaiyama Michael reaction. Mechanistic studies revealed that the Brønsted acid might be the predominant catalyst
A new Brønsted acid derived from squaric acid and its application to Mukaiyama aldol and Michael reactions
作者:Cheol Hong Cheon、Hisashi Yamamoto
DOI:10.1016/j.tetlet.2009.03.060
日期:2009.7
of silyl enol ether. The Brønsted acid was further applied to Mukaiyama Michael reaction of α,β-unsaturated ketones. It is noted that catalyst loading of all Mukaiyamareactions was only 1 mol % or less, which demonstrated the high reactivity of this acid. Mechanistic studies implied that the Mukaiyamaaldolreaction might proceed through Brønsted acid catalysis, rather than through Lewisacid catalysis