An asymmetric nitro-Mannich reaction applicable to alkyl, aryl, and heterocyclic imines.
[reaction: see text] A protocol for the enantioselective nitro-Mannich coupling between alkyl, aryl, and heterocyclic p-methoxybenzylimines and trimethylsilylnitropropanate catalyzed by a chiral tBu-BOX Cu(II) catalyst is described. It uses the lowest reported loading of commercially available metal catalyst and chiral ligand, and gives the highest yields and selectivities for a broad substrate range including nonaromatic aldimines. The resultant beta-nitroamines are obtained in 70-94% enantiomeric excess in good yield and can be readily reduced to synthetically useful 1,2-diamines.
School of Chemistry, University of Nottingham, NG7 2RD, United Kingdom. j.anderson@nottingham.ac.uk
James C
JC
Anderson
Gareth P
GP
Howell
Ron M
RM
Lawrence
Claire S
CS
Wilson