The copper/Rev-JosiPhos-catalysed asymmetric conjugate addition of Grignard reagents to 2methylcyclopentenone (1) provides 2,3-disubstituted cyclopentanones in high yields and enantioselectivities, and good diastereoselectivities. Reaction of the in situ formed enolate with various alkylating reagents in the presence of 1,3-dimethyltetrahydropyrimidine-2(1H)-one (DMPU) affords the correspond-ing products in a one-pot reaction. This procedure creates two vicinal stereocentres, one of them quaternary.

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Enones in which the carbon–carbon double bond is part of the pharmacologically important 2H-chromene (2H-1-benzopyran) nucleus undergo asymmetric copper-catalyzed 1,2-addition of Grignard reagents. High yields and enantiomeric excesses up to 84% are obtained and access to these novel enantio-enriched tertiary alcohols is provided.

Copper-Catalyzed Conjugate Addition of Grignard Reagents to 2-Methylcyclopentenone and Sequential Enolate Alkylation. -(CALVO, B. C.; MADDURI, A. V. R.; HARUTYUNYAN, S. R.; MINNAARD*, A. J.; Adv. Synth. Catal. 356 (2014) 9, 2061-2069, http://dx.doi.org/10.1002/adsc.201400085 ; Stratingh Inst. Chem., Univ. Groningen, NL-9747 AG Groningen, Neth.; Eng.) -F. Berndt 49-052