RHODIUM-CATALYZED MICHAEL ADDITIONS OF ACTIVATED NITRILES TO ALPHA,BETA-UNSATURATED ESTERS

The Michael additions of activated nitriles to methyl acrylate (MA) and methyl vinyl ketone (MVK) proceeds with fair to high yields (46-92%) in the presence of catalytic amount of HRh(CO)(PPh3)3 1 under mild eaction conditions. © 1983

Enantioselective michael additions of nitromethane to α,β-unsaturated ketones catalyzed by transition metal complexes with chiral nitrogen ligands

Nickel(II) complexes with chiral chelating nitrogen ligands such as 2,2'-bipyridines, 1,10-phenanthrolines and 1,2-diamino compounds are satisfactory catalysts for the Michael addition of nitromethane to benzalacetone, chalcone and 2-cyclohexenone. Only the catalytic system derived from Ni(acac)2 and (+)-(S)-2-(anilinomethyl)pyrrolidine gave both good catalytic activity and asymmetric induction up to 24%. © 1989

ASYMMETRIC MICHAEL ADDITIONS CATALYZED BY NI(II) AND CO(II) COMPLEXES WITH HOMOCHIRAL LIGANDS

Two Michael-type addition reactions of nitromethane to chalcone, reaction (1a), and of methyl 1-oxo-2-indanecarboxylate to methyl vinyl ketone (reaction (1b)) have been tested for catalytic asymmetric induction when carried out in the presence of Ni(II) or Co(II) and homochiral ligands. Proline-derived ligands in conjunction with Ni(II) are found to be moderately effective asymmetric inductors in the former addition (up to 59% e.e.). For this addition the absolute configuration of the adduct (2) has been established via correlation with (S)-(+)-1-(dimethylamino)-2,4-diphenylbutan-4-one (21). For reaction (1b), Co(II) complexes appear to be the more effective catalysts; the highest e.e. (38%) was obtained with a tetradentate ligand, a diaminodiol (16). Although the e.e.s so far obtained are not much better than those previously obtained, the method appears to allow further improvement. © 1991

Asymmetric Epoxidation by Mo(VI)-Peroxocomplexes: A Mechanistic Analysis

Abstrac