Palladium-catalyzed New Carbon-Phosphorus Bond Formation

Abstract

Dialkyl arylphosphonates are prepared by the palladium-catalyzed reaction of aryl bromides with dialkyl phosphite in the presence of triethylamine. The similar treatment of vinyl bromides gives dialkyl vinylphosphonates stereoselectively.

Pd-Catalyzed P-Arylation of Triarylantimony Dicarboxylates with Dialkyl H-Phosphites without a Base: Synthesis of Arylphosphonates

“…The crude residue was purified by column chromatograph (hexane-ethyl acetate) on silica gel to give arylphosphonates (10, 14-22). The products [10,37) 14, 37) 38) ] were colorless oil, and were confirmed by comparison of NMR data and MS spectra with that in the literature.…”

“…[7][8][9] With regard to the synthesis of arylphosphonates, the Pd-catalyzed cross-coupling reactions of aryl halides with dialkyl H-phosphites (i.e., Hirao P-arylation) have proved to be a powerful method. [10][11][12][13][14][15][16][17][18][19][20][21] The general procedure of these P-arylations involves a Pd-phosphine complex as the catalyst with the use of a stoichiometric or an excess amount of a base. Recently, different aryl substances were investigated for their reactivity with phosphorus agents.…”

Microwave-assisted Hirao reaction: recent developments

“…In their following report, Hirao and his group [12] also proposed a mechanism for the reaction. Palladium(0) is supposed to undergo oxidative addition with aryl-/vinyl halide to generate a palladium(II)-complex as the key intermediate.…”

“…In the early 1980s, Hirao and coworkers reported a phosphorus-carbon cross-coupling reaction of aryl-and vinyl halides with O,O-dialkyl phosphites in the presence of triethylamine (Et 3 N) and catalytic amount of tetrakis(triphenylphosphine)palladium [Pd(PPh 3 ) 4 ] to synthesize a variety of dialkyl aryl-and vinyl-phosphonates in good yields [10][11][12]. This reaction is now known as the Hirao reaction after the name of the inventor.…”

“…For example, phosphonation reaction of this complex can also be accomplished via an Arbusov-type reaction under classical heating with the same yield (81 %) but after 7 h at reflux [24]. Earlier in 1982, Hirao and his group observed that reaction between aryl halide and dialkylphosphite, catalyzed by palladium(0) complexes, is efficient but requires long time in hours (on average 10 h) [12].…”