title: Allylic substitution for construction of a chiral quaternary carbon possessing an aryl group.
abstract: Phenylcopper reagents derived from 2:1 PhMgBr/Cu(acac)2 and 3:1:1 PhMgBr/Cu(acac)2/ZnI2 were found to be highly reactive and regioselective in the allylic substitution of γ,γ-disubstituted secondary allylic picolinates designed for construction of a quaternary carbon, whereas the previous 2:1 ArMgBr/CuBr·Me2S reagent and that with ZnX2 were unsuccessful. The generality of the ArMgBr/Cu(acac)2 reagent was examined with enantiomerically enriched allylic picolinates, which furnished quaternary carbons with high efficiency in >92% regioselectivity and >97% chirality transfer. Two cyclohexanes with a quaternary carbon were synthesized by using these reagents.
authors.affiliation: Department of Bioengineering, Tokyo Institute of Technology, B52, Nagatsuta-cho 4259, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Chao
authors.initials: C
authors.lastname: Feng
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kobayashi
mesh_terms: D000498:Allyl Compounds; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D003510:Cyclohexanes / Q000737:chemistry*; D007202:Indicators and Reagents / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000498:Allyl Compounds; D003510:Cyclohexanes; D007202:Indicators and Reagents; D002244:Carbon; D003300:Copper