Palladium-Catalyzed Hydrophosphinylation of Alkenes and Alkynes

Abstract

Various palladium catalysts promote the addition of hypophosphorous derivatives ROP(O)H(2) to alkenes and alkynes in good yields and under mild conditions. Particularly, Cl(2)Pd(PPh(3))(2)/2 MeLi, and Pd(2)dba(3)/xantphos allow for phosphorus-carbon bond formation instead of transfer hydrogenation. Commercial aqueous solutions of hypophosphorous acid can be employed successfully at ambient temperature. With styrene and terminal alkynes, the regioselectivity (linear versus branched products) can be controlled to some extent with the catalytic system employed. The methodology considerably extends upon previous routes for the preparation of H-phosphinic acids and other organophosphorus compounds.

Synthesis of Disubstituted Phosphinates via Palladium‐Catalyzed Hydrophosphinylation of H‐Phosphinic Acids

“…[3] We have been involved in the development of methodologies for the preparation of H-phosphinates through the use of hypophosphorous acid (H 3 PO 2 ) and its derivatives. [4] This avoids hazardous and energy-wasteful phosphorus trichloride (PCl 3 ).…”

Recent advances in phosphorus–carbon bond formation: synthesis of H-phosphinic acid derivatives from hypophosphorous compounds

“…It was thought that the ligand could control the lifetime and reactivity of this species. This mechanism-based idea (Scheme 7), perhaps simplistic, turned out to be correct, at least in practice, and we were able to develop a unique catalytic P-C bond-forming reaction [39].…”

Recent Progress in Transition Metal-Catalyzed Addition Reactions of H–P(O) Compounds with Unsaturated Carbon Linkages

“…Hydrophosphorylation of alkenes and alkynes with phosphinic acid derivatives such as alkyl phosphinates [H 2 P(O)(OR)] and anilinium phosphinate [PhNH 3 ÁOP (O)H 2 ] is successfully catalyzed by palladium complexes, in particular those ligated by xantphos and dppf [25]. Polymer-bound palladium catalyst 11 has proved to catalyze the same reactions with phosphinic acid to give good yields, although the…”

“…Addition to olefins has not made an epoch-making progress since the publications on hydrophosphorylation using pinacol phosphonate [50] and unsubstituted phosphinic acid (hypophosphorous acid) derivatives [25], inclusive of the extension to rhodium-catalyzed reactions of pinacol phosphonate [51]. No publication has appeared to disclose addition reactions of a phosphine oxide except for cyclopropenes (vide infra).…”

“…Palladium complexes like Pd/xantphos are known to efficiently catalyze addition of alkyl phosphinates to terminal olefins to give linear adducts as the major products [25]. When the reaction of (À)-8-phenylmenthyl phosphinate with olefins is run using the Pd/xantphos catalyst, enantioselective addition proceeds to give diastereomeric mixtures of P-chiral (À)-8-phenylmenthyl alkylphosphinates (Scheme 55).…”