Combined α,α-dialkylprolinol ether/Brønsted acid promotes Mannich reactions of aldehydes with unactivated imines. An entry to anti-configured propargylic amino alcohols

摘要: The first enamine mediated anti-selective and highly enantioselective Mannich reaction of aldehydes unactivated imines is reported. key for success the combined use a Bronsted acid with an α,α-dialkylprolinol ether catalyst that leads to adducts good yields (typically 70–75%), anti : syn ratios greater than 90 : 10, ee values usually above 95%. method works particularly well propargylic and, unlike previous catalytic routes optically active propargylamines, provides featuring two contiguous stereocenters functionalized side chain amenable ulterior synthetic applications.