Highly enantioselective conjugate addition of AlMe3 to linear aliphatic enones by a designed catalyst.
2-Hydroxy-2'-alkylthio-1,1'-binaphthyl compounds are catalytic promoters of the 1,4-addition of AlMe(3) to linear aliphatic enones in THF at -40 to -48 degrees C in the presence of [Cu(MeCN)(4)]BF(4). At ligand loadings of 5-20 mol %, enantioselectivities of 80-93 % are realised for most substrates. To attain these values, the use of highly pure AlMe(3) is mandatory. The presence of methylalumoxane (MAO), derived by hydrolysis, leads to reduced enantioselectivity and a conjugate addition product.
Fraser
Paul K
PK
School of Chemistry, The University of Nottingham University Park, Nottingham NG7 2RD, United Kingdom.
Woodward
Simon
S