Ni(Ⅱ)-Bis[(R,R)-N,N′-dibenzylcyclohexane-1,2-diamine]Br_2 Catalyzed Enantioselective Michael Additions of 1,3-Dicarbonyl Compounds to Conjugated Nitroalkenes

摘要

The continued interest in the development of direct catalytic addition processes such as the Michael reaction is based on the wide variety of synthetically useful chiral building blocks that are readily assembled in the event that such processes can be rendered enantioselective. Products resulting from the enantioselective addition of nucleophiles to conjugated nitroalkenes represent attractive targets largely due to the attributes of the nitro group associated with its range of subsequent transformations. Recent studies by others have led to the development of catalytic enantioselective additions of 1,3-dicarbonyl compounds to conjugated nitroalkenes. The purpose of this communication is to introduce a new, readily prepared, chiral Ni(Ⅱ) catalyst 1 that facilitates this enantioselective transformation at ambient temperatures (Scheme 1).