Hydrophosphonylation of Alkynes with Trialkyl Phosphites Catalyzed by Nickel

• Published in: ChemCatChem Vol. 9; no. 21; pp. 4125 - 4131
• Main Authors: Islas, Rosa E., García, Juventino J.
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 09.11.2017
• Subjects: Alkynes; homogeneous catalysis; Inorganic salts; nickel; phosphorus; reaction mechanisms
• ISSN: 1867-3880; 1867-3899
• DOI: 10.1002/cctc.201700974

The use of simple and inexpensive NiCl2⋅6 H2O as a catalyst precursor for C−P bond formation in the presence of commercially available trialkyl phosphites (P(OR)3, R=Et, iPr, Bu, SiMe3) along with several alkynes is presented. Control experiments showed the in situ formation of (RO)2P(O)H as the species that undergo the addition into the C≡C bond at the alkynes to yield the product of P−H addition. The hydrophosphonylation of diphenylacetylene with P(OEt)3, P(OiPr)3, and P(OSiMe3)3 proceeds in high yields (>92 %) without the need of a specific solvent or ligand. This method is useful for the preparation of organophosphonates for both phenylacetylene as a terminal alkyne model and internal alkynes in yields that range from good to modest. Back to the hydrophosphonylation: The use of inexpensive NiCl2⋅6 H2O as a catalyst precursor for C−P bond formation in the presence of commercially available trialkyl phosphites (P(OR)3, R=Et, iPr, Bu, SiMe3) along with several alkynes is presented. (RO)2P(O)H formed in situ undergoes addition to the alkyne C≡C bond. The hydrophosphonylation of diphenylacetylene with P(OEt)3, P(OiPr)3, and P(OSiMe3)3 proceeds in high yields (>92 %) without the need of a specific solvent or ligand.