Halogen- and N-haloimide-promoted homo- and heterocoupling of alpha-(N-carbamoyl)alkylcuprates and alpha-(alkoxy)alkylcuprates.
Both homo- and mixed lithium di-alpha-(heteroatom)alkylcuprates readily dimerize upon addition of halogens (e.g., I(2), Br(2)) or N-halosuccinimides to afford the coupled products in excellent yields. Higher yields result when the requisite alpha-(heteroatom)alkyllithium reagents are generated via deprotonation rather than by transmetalation of the corresponding stannanes. Mixed lithium dialkyl- or alkyl(aryl)cuprate reagents containing one alpha-(heteroatom)alkyl ligand and one simple alkyl or aryl ligand give significantly lower yields of coupled product. Low enantioselectivity has been achieved in the oxidative coupling of lithium (n-Bu)(2-pyrrolidinyl)cuprate.
Dieter
R Karl
RK
Department of Chemistry, Hunter Laboratory, Clemson University, Clemson, South Carolina 29634-0973, USA. dieterr@clemson.edu
Li
ShengJian
S
Chen
Ningyi
N
D003300:Copper / Q000737:chemistry*; D006219:Halogens / Q000737:chemistry; D018020:Lithium Compounds / Q000138:chemical synthesis*; D015394:Molecular Structure; D013388:Succinimides / Q000737:chemistry
D006219:Halogens; D018020:Lithium Compounds; D013388:Succinimides; D003300:Copper