Conjugate Addition of α-Substituted Acyl Imidazoles to Nitroalkenes Catalyzed by Nickel Bisoxazoline and B(C6F5)3

A diastereoselective and enantioselective conjugate addition of alpha-substituted acyl imidazole to nitroalkene catalyzed by nickel bisoxazoline complex and B(C6F5)(3) has been developed. This reaction tolerated a wide range of acyl imidazoles and nitroalkenes, affording a series of conjugate adducts in yields ranging from 38% to 99% with 4:1 to 99:1 dr and 13% to 98% ee. The use of strong Lewis acid B(C6F5)(3) as co-catalyst proved vital to the success of this process. The potential scalability and utility of the current protocol are demonstrated by a reaction on a 3 mmol scale and further transformations of the product.

Automated summary

A diastereoselective and enantioselective conjugate addition of alpha-substituted acyl imidazole to nitroalkene catalyzed by nickel bisoxazoline complex and B(C6F5)(3) has been developed. The reaction showed broad substrate tolerance and high yields and enantioselectivity. The coordination catalyst and co-catalyst played a crucial role in the success of the reaction.