A Versatile Methodology for the Synthesis of α,β‐Unsaturated 3‐Iminophosphines

Abstract

Phorteen phine phosphines: Fourteen new alpha,beta-unsaturated beta-chloroimines were synthesized from inexpensive ketones by using the Vilsmeier-Haack reagent followed by Schiff-base condensation. Each imine was subsequently converted to an alpha,beta-unsaturated 3-iminophosphine through either late-metal-catalyzed phosphorus-carbon cross-coupling or through an addition-elimination sequence (see scheme). This high-yield protocol serves as a general means to produce alpha,beta-unsaturated 3-iminophosphines.Fourteen new alpha,beta-unsaturated beta-chloroimines were synthesized from commercially available ketones using the Vilsmeier-Haack reagent, followed by Schiff-base condensation. Each imine was subsequently converted to an alpha,beta-unsaturated 3-iminophosphine through either late-metal-catalyzed phosphorus-carbon cross-coupling or through an addition-elimination sequence. Depending on the substituents present on the vinyl group, the resultant phosphines were isolated as either E or Z diastereomers with successful isolation of predominately single diastereomers for all fourteen new phosphines investigated. Full synthetic and spectroscopic details, as well as several X-ray crystal structures of these new imines and phosphines, are reported in addition to X-ray crystal structures of related palladium complexes.