Quinidine Diels-Alder reaction

Based on the experiences on the Diels-Alder reaction of 2-pyrones [20], Deng et al. have investigated the stereoselective Diels-Alder reaction of 2-pyrones and a,(3-unsaturated ketones. They also found that primary amines lo and lp derived from quinine and quinidine, respectively, werethe optimal iminium catalysts (5 mol%). The acid additive has a crucial effect on the efficiency of the reaction. TFA (20 mol%) gave the best results, and the Michael reaction, as a side reaction, could also be prohibited. [Pg.314]

The hetero-Diels-Alder reaction between nascent ketenes generated from crotonyl chlorides and trichloroacetaldehyde, is effected by Sn(OTf)2, and rendered asymmetric by a TMS derivative of quinidine. ... [Pg.173]

The first asymmetric chiral-base catalyzed Diels-Alder reaction of anthrone 79 with maleimide 80 was achieved by Kagan and Riant in 1989 [4]. With the use of quinidine (81) as catalyst, the cycloadduct 83a can be obtained in 97% yield with 61% ee (Scheme 38.23). The enantioselectivity was further improved to 87% by... [Pg.1144]

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