Biphilic Organophosphorus Catalysis: Regioselective Reductive Transposition of Allylic Bromides via PIII/PVRedox Cycling
摘要:
We report that a regioselective reductive transposition of primary allylic bromides is catalyzed by a biphilic organophosphorus (phosphetane) catalyst. Spectroscopic, evidence supports the formation of a penta:coordinate (sigma(5)-P) hydridophosphorane as a key reactive intermediate. Kinetics experiments and computational modeling are consistent with a unimolecular docomposition of the sigma(5)-P hydridophosphorane via a conceited cyclic transition,structure that delivers the observed allylic transposition and completes a novel P-III/P-V redox Catalytic cycle. These results broaden the growing repertoire., of reactions catalyzed within the P-III/P-V redox couple and suggest additional opportunities for organophosphorus,catalysis in a biphilic mode.
Further ring openings and ring expansions of phosphetans
作者:J. R. Corfield、M. J. P. Harger、J. R. Shutt、S. Trippett
DOI:10.1039/j39700001855
日期:——
4-hexamethyl-1-phenylphosphetanium iodide led to ring opening via pentacovalentintermediates as also did the action of cyanide ion on this salt. Ring expansions of 2,2,3-trimethyl- and 2,2,3,3-tetramethyl-1-phenylphosphetan on reaction with ethyl propiolate in wet ether, on reaction with dimethyl acetylenedicarboxylate, and on hydrolysis of the iodomethylphosphetanium salts, occur with migration of the
Hydrolysis of a phosphonium salt. Encounter-limited, rate-determining breakdown of a pentacovalent intermediate
作者:David. Gorenstein
DOI:10.1021/ja00805a019
日期:1973.11
The pH-rateprofile for the hydrolysis of 1-methoxy-I-phenyl2,2,3- trimethylphosphetanium hexafluorophosphate is presented. The rate of hydrolysis is proportional to the hydroxide ion concentration in the alkaline region, pH > 9, and is pH independent in dilute acid. In the moderate to strong acid region (pH < 1) the rate decreases with increasing acidity, attributable to a decrease in the activity
A proppant comprises a particle and a polycarbodiimide coating disposed on the particle. The polycarbodiimide coating comprises the reaction product of an isocyanate reacted in the presence of a phospholene oxide catalyst. A method of forming the proppant comprises the steps of providing the particle, providing the isocyanate, providing the phospholene oxide catalyst, reacting the isocyanate in the presence of the phospholene oxide catalyst to form the polycarbodiimide coating, and coating the particle with the polycarbodiimide coating.
A Proppant
申请人:BASF SE
公开号:US20150315458A1
公开(公告)日:2015-11-05
A proppant includes a surface treatment comprising an antistatic component and a hydrophilic component. The antistatic component comprises a quaternary ammonium compound. The hydrophilic component comprises a polyether polyol. A method of forming the proppant comprises the step of applying the surface treatment onto the proppant.