Phosphorochloridite

In chemistry, phosphorochloridites are a class of organophosphorus compound with the formula (RO)₂PCl (R = organic substituent). They are pyramidal in shape, akin to regular phosphites (P(OR)₃). They are usually colorless and sensitive toward hydrolysis and, to some extent, oxidation to the corresponding phosphorochloridates ((RO)₂P(O)Cl).

Synthesis and reactions

Structure of 2,2'-biphenylene phosphorochloridite.

Phosphorochloridites are produced by partial alcoholysis of phosphorus trichloride, which proceeds stepwise:^[1]

PCl₃ + ROH → HCl + (RO)PCl₂ (phosphochloridite)

(RO)PCl₂ + ROH → HCl + (RO)₂PCl (phosphodichloridite)

(RO)₂PCl + ROH → HCl + (RO)₃P (phosphite)

These reactions are readily controlled with aromatic diols, such as binaphthol and 2,2'-biphenol.

Phosphorochloridites are precursors to diphosphite ligands. When combined with rhodium precursors such as Rh(acac)(CO)₂, these diphosphite ligands afford catalysts that are used industrially for the hydroformylation of alkenes.^[2] it and related ligands have become popular in hydroformylation catalysis.^[3]^[4]

References

^ Gual, Aitor; Godard, Cyril; de la Fuente, Verónica; Castillón, Sergio (2012). "Design and Synthesis of Phosphite Ligands for Homogeneous Catalysis". Phosphorus(III) Ligands in Homogeneous Catalysis: Design and Synthesis. pp. 81–131. doi:10.1002/9781118299715.ch3. ISBN 9781118299715.
^ Billig, Ernst; Abatjoglou, Anthony G.; Bryant, David R. (1988). "Homogeneous Rhodium Carbonyl Compound-Phosphite Ligand Catalysts and Process for Olefin Hydroformylation". US 4769498 a 19880906 to Union Carbide.
^ Cuny, Gregory D.; Buchwald, Stephen L. (1993). "Practical, High-Yield, Regioselective, Rhodium-Catalyzed Hydroformylation of Functionalized α-olefins". Journal of the American Chemical Society. 115 (5): 2066–2068. doi:10.1021/ja00058a079.
^ Van Rooy, Annemiek; Kamer, Paul C. J.; Van Leeuwen, Piet W. N. M.; Goubitz, Kees; Fraanje, Jan; Veldman, Nora; Spek, Anthony L. (1996). "Bulky Diphosphite-Modified Rhodium Catalysts: Hydroformylation and Characterization". Organometallics. 15 (2): 835–847. doi:10.1021/OM950549K.

[1] Gual, Aitor; Godard, Cyril; de la Fuente, Verónica; Castillón, Sergio (2012). "Design and Synthesis of Phosphite Ligands for Homogeneous Catalysis". Phosphorus(III) Ligands in Homogeneous Catalysis: Design and Synthesis. pp. 81–131. doi:10.1002/9781118299715.ch3. ISBN 9781118299715.

[2] Billig, Ernst; Abatjoglou, Anthony G.; Bryant, David R. (1988). "Homogeneous Rhodium Carbonyl Compound-Phosphite Ligand Catalysts and Process for Olefin Hydroformylation". US 4769498 a 19880906 to Union Carbide.

[3] Cuny, Gregory D.; Buchwald, Stephen L. (1993). "Practical, High-Yield, Regioselective, Rhodium-Catalyzed Hydroformylation of Functionalized α-olefins". Journal of the American Chemical Society. 115 (5): 2066–2068. doi:10.1021/ja00058a079.

[4] Van Rooy, Annemiek; Kamer, Paul C. J.; Van Leeuwen, Piet W. N. M.; Goubitz, Kees; Fraanje, Jan; Veldman, Nora; Spek, Anthony L. (1996). "Bulky Diphosphite-Modified Rhodium Catalysts: Hydroformylation and Characterization". Organometallics. 15 (2): 835–847. doi:10.1021/OM950549K.

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