Generation of Phosphonium Sites on Sulfated Zirconium Oxide: Relationship to Brønsted Acid Strength of Surface −OH Sites
作者:Jessica Rodriguez、Damien B. Culver、Matthew P. Conley
DOI:10.1021/jacs.8b13204
日期:2019.1.30
(2a-h). The equilibrium binding constants of 1a-h to SZO300 are related to the p Ka of [(tBu)2ArPH]; R3P that form less acidic phosphoniums (high p Ka values) bind stronger to SZO300 than R3P that form more acidic phosphoniums (low p Ka values). These studies show that Brønstedacidsites on the surface of SZO300 are not superacidic.
(tBu)2ArP (1a-h),其中 Ar 基团的对位含有给电子或吸电子基团,与在 300 °C 下部分脱羟基的硫酸化氧化锆 (SZO300) 的反应形成 [(tBu)2ArPH ][SZO300] (2a-h)。1a-h 与 SZO300 的平衡结合常数与 [(tBu)2ArPH] 的 p Ka 相关;形成酸性较低的鏻(高 p Ka 值)的 R3P 与 SZO300 的结合比形成更多酸性鏻(低 p Ka 值)的 R3P 更强。这些研究表明 SZO300 表面的布朗斯台德酸位不是超酸性的。
Reductive cleavage of the carbonphosphorus bond with alkali metals. III. Reactions of arylalkylphosphines
作者:Johannes A. van Doorn、Nico Meijboom
DOI:10.1002/recl.19921110402
日期:——
The reductive cleavage of phenylalkylphosphines Ph2PR, PhPR2 (R = Bu, iPr) with Na/NH3 is unselective: both phenyl and alkyl groups can be cleaved and Birch reduction may occur. Reaction of Ph2tBuP gives a high yield of diphenylphosphide. Polar groups (CO2Na, SO3,Na) at the ω position of primary alkyl groups may lead to an increase in selectivity; Birch reduction is suppressed and a functionalised
and/or alkyllithium species reacted smoothly with aryl and/or benzyl ethers with cleavage of the inert C−O bond to afford cross‐coupled products, catalyzed by commercially available [Ni(cod)2] (cod=1,5‐cyclooctadiene) catalysts with N‐heterocyclic carbene (NHC) ligands. Furthermore, the couplingreaction between the aryllithium compounds and aryl ammonium salts proceeded under mild conditions with C−N
Easy one-pot access to substituted 2-phenylpyrrolines from 2-pyrrolidinone
作者:Cécile Coindet、Alain Comel、Gilbert Kirsch
DOI:10.1016/s0040-4039(01)01192-3
日期:2001.8
An easyaccess to 2-aryl pyrrolidines is the reduction, stereospecific or not, of the corresponding 2-aryl-pyrroline (5-aryl-3,4-dihydro-2H-pyrrole). Preparation of the latter has been carried out from 2-pyrrolidinone using an easy one-pot two-step method for the first time.
Formation of Boroxine: Its Stability and Thermodynamic Parameters in Solution
作者:Yuji Tokunaga、Hiroki Ueno、Youji Shimomura、Toshihiro Seo
DOI:10.3987/com-02-9464
日期:——
Condensation of three boronic acids proceeding at room temperature gave their corresponding boroxines; NMR spectral measurements revealed that the reaction was reversible at room temperature, that electron-donating groupssupported the formation of boroxine, and that entropically driven forces promoted the formation of boroxine in solution.