X=Y–ZH Systems as potential 1,3-dipoles. Part 54: Stereo- and facially-selective formation of bridged bicyclic N-heterocycles via a sequential one-pot electrophile induced oxime→nitrone→cycloaddition sequence. Multiplication of chirality

Abstract

Electrophile induced bridged-ring forming cyclisations creating azabicyclo-[3.3.1]- and azabicyclo-[3.2.1]-nitrones, followed by cycloaddition, occur stereo-, regio- and facially specifically in good to excellent yield. Chiral bridged-ring systems have been synthesised that involve multiplication of chiral centres from one to six and one to seven in one pot reactions.