71265-08-2Relevant articles and documents
Hydrophosphorylation of Alkynes Catalyzed by Palladium: Generality and Mechanism
Chen, Tieqiao,Zhao, Chang-Qiu,Han, Li-Biao
, p. 3139 - 3155 (2018)
We carried out a comprehensive study on the generality, scope, limitations, and mechanism of the palladium-catalyzed hydrophosphorylation of alkynes with P(O)-H compounds (i.e., H-phosphonates, H-phosphinates, secondary phosphine oxides, and hypophosphinic acid). For H-phosphonates, Pd/dppp was the best catalyst. Both aromatic and aliphatic alkynes, with a variety of functional groups, were applicable to produce the Markovnikov adducts in high yields with high regioselectivity. Aromatic alkynes showed higher reactivity than aliphatic alkynes. Terminal alkynes reacted faster than internal alkynes. Sterically crowded H-phosphonates disfavored the addition. For H-phosphinates and secondary phosphine oxides, Pd/dppe/Ph2P(O)OH was the catalyst of choice, which led to highly regioselective formation of the Markovnikov adducts. By using Pd(PPh3)4 as the catalyst, hypophosphinic acid added to terminal alkynes to give the corresponding Markovnikov adducts. Phosphinic acids, phosphonic acid, and its monoester were not applicable to this palladium-catalyzed hydrophosphorylation. Mechanistic studies showed that, with a terminal alkyne, (RO)2P(O)H reacted, like a Br?nsted acid, to selectively generate the α-alkenylpalladium intermediate via hydropalladation. On the other hand, Ph(RO)P(O)H and Ph2P(O)H gave a mixture of α- and β-alkenylpalladium complexes. In the presence of Ph2P(O)OH, hydropalladation with this acid took place first to selectively generate the α-alkenylpalladium intermediate. A subsequent ligand exchange with a P(O)H compound gave the phosphorylpalladium intermediate which produced the Markovnikov adduct via reductive elimination. Related intermediates in the catalytic cycle were isolated and characterized.
Synthesis of Alkenylphosphonates through Palladium-Catalyzed Coupling of α-Diazo Phosphonates with Benzyl or Allyl Halides
Zhou, Yujing,Ye, Fei,Wang, Xi,Xu, Shuai,Zhang, Yan,Wang, Jianbo
, p. 6109 - 6118 (2015/06/30)
An efficient method for the synthesis of organophosphonates through palladium-catalyzed coupling of α-diazo phosphonates with benzyl or allyl halides has been developed. Trisubstituted alkenylphosphonates bearing versatile functional groups can be easily accessed in good yields and with excellent stereoselectivity through this method. Moreover, with similar strategy α-substituted vinylphosphonates can also be attained by the palladium-catalyzed coupling reaction of N-tosylhydrazones and aryl bromides. Migratory insertion of palladium carbene is proposed as the key step in this reaction.
Acylphosphonates as Substrates for Wittig and Horner-Wittig Reactions. Unusual Stereoselectivity in the Synthesis of β-Phosphinoylacrylates
Harris, Roger L. N.,McFadden, Helen G.
, p. 417 - 424 (2007/10/02)
Phosphorus-stabilized carbanions with additional stabilizing groups react with dialkyl acylphosphonates (alkanoyl- and aroyl-phosphonates) to give fair to good yields of dialkyl vinylphoshponates, with some limitations imposed by competing side reactions
