Final Activity Report Summary - BICATORG (Self-hidden Bifunctional Organocatalysts for Organic Synthesis)
Taking into account the increasing interest for poly-functional compounds combining donor and acceptor moieties, the first objective of this project was to expand the variety of available phosphine-borane derivatives. In this regard, the incorporation of flexible ferrocenyl and diphenylether spacers represented an important achievement.
The second objective was to define new fields of interest for these ambiphilic derivatives through their reaction with organic partners. We were particularly interested in evidencing their ability to stabilise reactive intermediates. Accordingly, the o-R2P(Ph)BR'2 skeleton was demonstrated to form a highly stable 'carbene adduct', whose Wittig-type reactivity completely vanished due to strong intramolecular interaction with the Lewis acid. Studying the related nitrene adducts, the intermediate phosphasides were found to be dramatically stabilised as well. Aiming at promoting the nitrogen evolution photochemically, an original coordination isomerisation was observed. Accordingly, ambiphilic derivatives were found to provide general heterodiene scaffolds for new photoisomerisable systems.
The third and last objective was to evaluate representative phosphine-borane gold(I) complexes in the catalysis. Preliminary results suggested a subtle interplay between electronic and steric effects. Ongoing work aimed to take advantage of the boron Lewis acid to increase the activity and selectivity compared to catalysts derived from simple phosphines.
The second objective was to define new fields of interest for these ambiphilic derivatives through their reaction with organic partners. We were particularly interested in evidencing their ability to stabilise reactive intermediates. Accordingly, the o-R2P(Ph)BR'2 skeleton was demonstrated to form a highly stable 'carbene adduct', whose Wittig-type reactivity completely vanished due to strong intramolecular interaction with the Lewis acid. Studying the related nitrene adducts, the intermediate phosphasides were found to be dramatically stabilised as well. Aiming at promoting the nitrogen evolution photochemically, an original coordination isomerisation was observed. Accordingly, ambiphilic derivatives were found to provide general heterodiene scaffolds for new photoisomerisable systems.
The third and last objective was to evaluate representative phosphine-borane gold(I) complexes in the catalysis. Preliminary results suggested a subtle interplay between electronic and steric effects. Ongoing work aimed to take advantage of the boron Lewis acid to increase the activity and selectivity compared to catalysts derived from simple phosphines.