Stereospecific Construction of Chiral Quaternary Carbon Compounds from Chiral Secondary Alcohol Derivatives

Chiral tertiary dichloromethylcarbinol derivatives, prepared by stereospecific α C–H insertion reaction of dichlorocarbene with protected chiral secondary alcohols, were converted into intermediary α-chloroepoxides which gave stereospecifically chiral quaternary carbon compounds, α-aminoacids via α-azide-aldehydes and α-cyanoacetic acids through cyanation, respectively. The fashion generating the quaternary centers from dichloromethylcarbinols via α-chloroepoxides was proved to be quite different depending on the substrates: inversion of configuration of non-benzylic substrates and apparent retention with benzylic one.