A New Methodology for Synthesis of a Chiral Phosphinocarboxylic Acid through Michael Cyclization−Aldol Tandem Reaction of Chiral α,β,χ,ψ-Unsaturated Bisphosphine Oxide and Application in Palladium-Catalyzed Asymmetric Allylic Alkylation
2002-07-11T00:00:00Z (GMT) by
Upon successive treatment with lithium diisopropylamide and then benzaldehyde, a chiral α,β,ψ,ω-unsaturated bisphosphine oxide underwent Michael cyclization−aldol tandem reaction to afford the corresponding endo-α,β-unsaturated cyclic bisphosphine oxides. Sequential stereoselective reduction and Horner−Wadsworth−Emmons olefination gave the corresponding monophosphine oxide. Oxidative conversion of an olefin moiety into a carboxyl group and subsequent deoxygenation of an oxide gave the corresponding chiral phosphinocarboxylic acid, which was successfully applied as a chiral and functionalized monophosphine ligand in a palladium-catalyzed asymmetric allylic alkylation.
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