Molecular topology: The synthesis of a new class of rigid arc-shaped spacer molecules based on syn-facially fused norbornanes and 7-heteronorbornanes in which heterobridges are used to govern backbone curvature

Abstract

Norbornadienes and 7-heteronorbornadienes are reacted with 7-oxa (or carba or aza) norbornene-fused cyclobutene epoxides (or aziridines) to produce hetero-bridged polynorbornane cycloadducts containing syn-facially arranged N,O (or C,N or C,O) bridges. New dual cyclobutene epoxides and dual cyclobutene aziridines are used to prepare multi-fused norbornanes having curved topology in which the heteroatoms modify the curvature in a predictable way C>N>O; AM1 modelling of representative [9]polynorbornanes is prosented.