Early Steps of Homogeneous Catalysis in Rennes: Carbon Dioxide Incorporation, Alkyne Activation and Ruthenium Catalysis
Résumé
This review reports the first discoveries in homogeneous catalysis in Rennes. Ruthenium(II) catalysts are shown to promote the activation of terminal alkynes and the synthesis of vinylcarbamates on addition of CO2 and amines. The ruthenium–vinylidene are the key catalytic species. Applications to the addition of carboxylic acids to alkynes have opened the access to various enolesters and dienylesters via controlled catalyzed Markovnikov or anti-Markonikov additions. The catalytic synthesis of α-methylene cyclic carbonates and oxazolidinones from propargylic alcohols and CO2 is presented and shown to lead to allene derivatives via palladium catalysis. Cp*RuX(COD) catalyst promote the head to tail oxidative couplings of alkene with alkyne, and the synthesis of functional dienes via 1,4 addition of H-nucleophiles to the biscarbene-ruthenium intermediate arising from head to head couplings of alkynes, whereas Cp*RuL2 + catalysts favour activation of alkynes via vinylidene intermediate.