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Catalytic Asymmetric Direct-Type 1,4-Addition Reactions of Simple Amides

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posted on 08.04.2015, 00:00 by Hirotsugu Suzuki, Io Sato, Yasuhiro Yamashita, Shu̅ Kobayashi
The development of catalytic asymmetric direct-type reactions of less acidic carbonyl compounds such as amides and esters has been a challenging theme in organic chemistry for decades. Here we describe the asymmetric direct 1,4-addition reactions of simple amides with α,β-unsaturated carbonyl compounds using a catalytic amount of a novel chiral catalyst consisting of a potassium base and a macrocyclic chiral crown ether. The desired 1,5-dicarbonyl compounds were obtained in high yields with excellent diastereo- and enantioselectivities. This is the first example of a highly enantioselective catalytic direct-type reaction of simple amides. In addition, the structure of the chiral potassium catalyst has been investigated by X-ray crystallographic, dynamic 1H NMR, and MALDI-TOF MS analyses.