Catalytic Synthesis of Nonracemic Azaproline Derivatives by Cyclization of β-Alkynyl Hydrazines under Kinetic Resolution Conditions
作者:Pradip Maity、Salvatore D. Lepore
DOI:10.1002/anie.201101090
日期:2011.8.29
accessible γ‐silyl allenyl esters, β‐alkynyl hydrazines were prepared in one step and subsequently cyclized in the presence of ammonium and phosphonium catalysts leading to dehydroazaproline products (see scheme; X=O, S). These heterocycles were also produced in high enantiomeric excesses using chiral ammonium phase‐transfer catalysts by a kineticresolution.