Molecular sieve mediated decarboxylative Mannich and aldol reactions of β-ketoacids
作者:Fangrui Zhong、Chunhui Jiang、Weijun Yao、Li-Wen Xu、Yixin Lu
DOI:10.1016/j.tetlet.2013.06.030
日期:2013.8
A molecular sieve mediated decarboxylativeMannichreaction of β-ketoacids with sulfonyl imines is reported; this protocol leads to an efficient preparation of synthetically useful β-amino ketones. An analogous molecular sieve promoted decarboxylative aldol reaction between β-ketoacids and isatins is also described, which affords bioactive 3-substituted-3-hydroxy-oxindoles in excellent yields.
Base-catalyzed three-component direct Mannich reaction of enolizable ketones with high syn-selectivities
作者:Qunsheng Guo、John Cong-Gui Zhao、Hadi Arman
DOI:10.1016/j.tetlet.2012.06.140
日期:2012.9
The three-component direct Mannichreaction between aldehydes, p-toluenesulfonamide, and enolizable ketones was achieved for the first time with organic bases as the catalysts. The corresponding N-tosylated β-aminoketones were obtained in high yields and good to excellent diastereoselectivities using TMG as the catalyst. Through reduction of the ketone group, the reaction product may be converted into
Treatment of N-tosylaldimines with acetophenone at room temperature in the presence of Bf(3)center dot OEt2 as a catalyst furnished the corresponding N-tosyl beta-amino ketones in high yields (77-86%) within 6-9 h. Subsequent reduction and cyclization of these compounds afforded 2,4-disubstituted N-tosylazetidines, comprising a three-step, high-yielding synthesis starting from aldimines.