Easily Accessible and Highly Tunable Bisphosphine Ligands for Asymmetric Hydroformylation of Terminal and Internal Alkenes

摘要

An efficient methodology for synthesizing a small library of easily tunable and sterically bulky ligands for asymmetric hydroformylation(AHF) has been reported. Five groups of alkene substrates have been tested with excellent conversions, moderate-to-excellent regio-and enantioselectivities. Among the best result of the reported literature, application of ligand 1c in the highly selective AHF of the challenging substrate 2,5-dihydrofuran yielded almost one isomer in up to 99% conversion along with enantiomeric excesses(ee) of up to 92%. Highly enantioselective AHF of dihydropyrrole substrates is achieved using the same ligand, with up to 95% ee and up to >1:50 b-isomer/a-isomer ratio.