Position-Addressable Nano-Scaffolds. I. The Preparation of N,O-, N,C- and N,N-Bridged Sesquinorbornadiene Succinimides as Compact, Highly Functionalized Addressable Building Blocks

Abstract

Succinimide-functionalized N,O-, N,C-, and N,N-bridged benzo[2]polynorbornanes (benzosesquinorbornadienes) are reported for the first time and are prepared by the cycloaddition of either five-membered cyclic 1,3-dienes onto N-substituted benzo-7-azanorbornadienomaleimides or N-substituted isoindoles onto the appropriate norbornadienomaleimides. These products contain an end-fused norbornene (or a 7-substituted relative) and have been designed to act as alkene BLOCKs for the production of nano-scaffolds with up to six addressable sites supplied by each norbornene unit. The N-bridges in these BLOCKs (and their coupled products) allow N-substituent mobility by invertomerization of the sp³ nitrogen whereas the N-substituents on the succinimides are attached to an sp² nitrogen atom and remain static. Preferred invertomer geometry can be determined using molecular modelling.