Cooperative catalytic Prins cyclization for the construction of azaspiro[5.5]undec-2-ene frameworks

Abstract

Homoallylic alcohols appended with N-propargyl moiety undergo a smooth condensation with aldehydes in the presence of 5 mol% of Ph3PAuCl/AgSbF6/In(OTf)3 catalytic system in dichloromethane at 25 °C to afford the corresponding 1,9-dioxa-4-azaspiro[5.5]undec-2-ene scaffolds in good yields. This is the first report on the synthesis of azaspiro[5.5]undec-2-enes using a cooperative catalytic system.