A chiral pyrrolidine-pyrazole catalyst for the enantioselective Michael addition of carbonyls to nitroolefins

An enantioselective Michael reaction of carbonyl compounds to nitroolefins has been accomplished using a novel chiral pyrrolidine-pyrazole catalyst. This newly prepared catalyst was found to be very effective in providing good yields as well as good diastereo- and enantio-selectivities. The mechanism of the reaction has also been substantiated by mass spectral studies.

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(S)-tert-Butyl-2-((1H-pyrazol-1-yl)methyl)pyrrolidine-1-carboxylateC13H21N3O2[α]D25=-119 (c 1.1, CHCl3)Source of chirality: l-prolineAbsolute configuration: (S)

(S)-1-(Pyrrolidin-2-ylmethyl)-1H-pyrazoleC8H13N3[α]D25=-98 (c 0.9, CHCl3)Source of chirality: l-prolineAbsolute configuration: (S)