Enantioselectivity conjugate additions of malonates

Preliminary studies led to the employment of the Cinchona alkaloid catalysts 144 [230], 145 [231], and 146 [232] in the enantioselective conjugate addition of malonates to enones in the presence of K COj as base Fig. 2.14. Different fragances... 

Scheme 5.115 Enantioselective conjugate addition of malonates 448 to cyclopentenone, mediated by Shibasaki s catalyst 449 and subsequent aldol addition. Conversion of adduct 452 into 11-deoxy-PGF, .

The conjugate addition of aromatic and ahphatic a-nitro-ketones to a,p-unsaturated-a-keto esters was also reported to be catalyzed efficiently and with moderate to high enantioselectivity by 23 [74]. In addition, 23 appeared to catalyze the enantioselective conjugate addition of malonates to nitroenynes to furnish chiral P-alkynyl esters (Scheme 6.32) [75]. In a recent study, 23 was shown to catalyze the formation of chiral 4-nitro-cyclohexanones via a double conjugate addition reaction of nitromethane to dienones (Scheme 6.33) [76]. 

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