The dramatic improvement in diphenylzinc addition to aldehydes that is obtained by adding diethylzinc was investigated by DFT methods. The strong preference for phenyl over ethyl transfer can be understood in terms of overlap with the phenyl 31 system in the transition state (see picture). Reasons for the high ee value in the presence of Et$-2$/Zn are discussed.
|Journal||Angewandte chemie-international edition|
|Publication status||Published - 2003|