Dicyclohexylphosphinic acid

A variety of oligomers with novel drum and ladder structures have also been prepared. They have the formulas [R Sn(0)02CR]6 and [(R Sn(0)02CR)2 R Sn(02CR)3 2, and contain four- and six-membered rings. They can be synthesized by the reaction of stannoic acid with a carboxylic acid, but the reaction of RSnCl3 with the silver salt of a carboxylic acid can also be used. If diphenylphosphinic acid or dicyclohexylphosphinic acid is used instead of the carboxylic acid, oxygen-capped clusters or cubic and butterfly structures are obtained.69... 

Dicyclohexylphosphine oxide would thermally disproportionate into dicyclohexylphosphinic acid and dicyclohexylphosphine. We found that both the phosphine oxide, m.p. 72°-75°C., at 15%, and the phosphinic acid, m.p. 144°-145°C., at 5%, in polyethylene are flame retardants. 

Dicyclohexylphosphine oxide CyiV O) [14717-29-4] M 214.3, m 72.5-74.5°. The oxide crystallises from hexane or CgH6. It is tautomeric with dicyclohexylphosphinous acid (Cy2P-OH), whose Ethyl ester ([80413-46-3] M 242.3, obtained from CyP2Cl [16523-54-9] and EtOH) distils at lll-113°/lmm, 1.4950. 

With the aim of designing new and more efficient catalysts for Suzuki reaction, the bulky and electron-rich dialkylbiaryl phosphine ligands (Fig. 3.9) were found to dramatically improve the efficiency and selectivity of this type of reactions [76]. In particular, Buchwald s group reported that the use of 2-(2, 6 -dimethoxybi-phenyl)-dicyclohexylphosphine, SPhos (Fig. 3.9) in the palladium-catalyzed Suzuki reaction exhibited unprecedented scope, reaction rate, and stability [77]. More specifically, the use of this ligand conferred to the catalyst a unique activity allowing the coupling of boronic acids with aryl bromides and chlorides with low... 

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