Palladium-catalyzed C–P cross-coupling of allenic alcohols with H-phosphonates leading to 2-phosphinoyl-1,3-butadienes

Abstract

The first facile, efficient, atom-economical and regioselective palladium-catalyzed direct C-P cross-coupling of unprotected allenic alcohols with H-phosphonates for the one-pot synthesis of structurally diverse multisubstituted 2-phosphinoyl-1,3-butadienes was developed. The strategy...

Deciphering the Chameleonic Chemistry of Allenols: Breaking the Taboo of a Onetime Esoteric Functionality

“…Added value to this acid-promoted metal-free methodology is given by further applicability of halogenated dienes 180 on epoxidation or Suzuki-type reactions, providing tetrasubstituted epoxides 181 and arylsubstituted dienes 182, respectively (Scheme 33). 192,193 A conceptually different approach for the synthesis of dienes was based on a S N 2′ reaction in 1-acetoxy-2-allenoates 183.…”

“…Added value to this acid-promoted metal-free methodology is given by further applicability of halogenated dienes 180 on epoxidation or Suzuki-type reactions, providing tetrasubstituted epoxides 181 and aryl-substituted dienes 182 , respectively (Scheme ). , …”

Catalytic Hydrophosphination of Allenes Using an Iron(II) β-Diketiminate Complex

“…12 There are also a range of palladium-catalyzed reactions using P(V) sources of phosphorus work including hydrophosphination using pinacol phosphonate, 13 hypophosphorous acid 14 and H-phosphonates. 15 Lu and co-workers have used a catalytic amount of tertiary phosphine to undertake [3+2] cycloadditions of allene substrates, forming cyclopentene products. 16 More recently, this transformation has been studied in detail by Ofial and coworkers, with vinyl phosphonium intermediates being trapped to allow characterization of the phosphine addition products, 17 whose chemoselectivity is similar to that obtained from a hydrophosphination reaction.…”

“…12 There are also a range of palladium-catalyzed reactions using P(V) sources of phosphorus, including hydrophosphination using pinacol phosphonate, 13 hypophosphorous acid 14 and H-phosphonates. 15 Lu and co-workers have used a catalytic amount of We have previously reported hydrophosphination reactions utilizing alkenes and alkynes catalyzed by various iron complexes, 18 as well as nickel-catalyzed 19 and basemediated 20 methods. We were interested to see if iron complexes 1 or 2 (see Scheme 1) would be capable catalysts for the hydrophosphination of allenes.…”

“…12 There are also a range of palladium-catalyzed reactions using P(V) sources of phosphorus, including hydrophosphination using pinacol phosphonate, 13 hypophosphorous acid 14 and H-phosphonates. 15 Lu and co-workers have used a catalytic amount of C. R. Woof et al…”