Synthesis and application of chiral bisphosphines through lithiation–conjugate addition tandem cyclization of chiral α,β,ψ,ω-unsaturated bisphosphine oxide

Abstract

Upon treatment with lithium diisopropylamide achiral and chiral α,β,ψ,ω-unsaturated bisphosphine oxides underwent lithiation–conjugate addition tandem cyclization to afford the corresponding endo-α,β-unsaturated cyclic bisphosphine oxides; sequential stereoselective reduction of the cyclized bisphosphine oxide gave the corresponding trans- and cis-bisphosphines that were successfully applicable in a catalytic asymmetric hydrogenation as chiral bisphosphine ligands.