Phosphaalumenes react with alkynes and alkenes. Depending on the steric profile of the alkyne either 1,2-phosphaalumetes in a formal [2 2] cycloaddition or zwitterionic 1,4-phosphaaluminabarrelenes through threefold insertion into the Al−P bond are obtained. With alkenes 1,2-phosphalumates and 1,4-aluminaphosphorinanes are obtained. Computational studies corroborate the contrasting pathways and underline
6-iPr2C6H3)2C6H3), TipTer 2,6-(2,4,6-iPr3C6H2)2C6H3 was investigated. While no thermal reaction was observed (in line with DFT results), irradiation at 405 nm at low temperatures resulted in the formation of phosphagallenes DipTerP = GaCp* (1a) and TipTerP = GaCp* (1b) accompanied by release of PMe3. When warming the reaction mixture to ambient temperatures without irradiation, the clean re-formation
Cp*Ga (Cp* = C 5 Me 5 ) 对Ar TerP(PMe 3 ) ( Ar Ter = Dip Ter 2,6-(2,6-iPr 2 C 6 H 3 ) 2 C 6 H 3 ), Tip Ter 2,6-(2,4,6-iPr 3 C 6 H 2 ) 2 C 6 H 3被研究。虽然没有观察到热反应(与 DFT 结果一致),但在低温下以 405 nm 照射会导致形成磷四烯Dip TerP = GaCp* ( 1a ) 和Tip TerP = GaCp* ( 1b ) 伴随着 PMe 3的释放。当在没有辐射的情况下将反应混合物加热至环境温度时,观察到Ar TerP(PMe 3 ) 和 Cp*Ga 在二级反应中的干净再形成去除 PMe 3后,分离出1a和1b并对其进行充分表征。发现这两种衍生物都不稳定并分解为磷芴2a和2b,表明瞬时亚膦基Ar的生成TerP 与 Cp*Ga。首次反应性研究表明,CO
An Unusual Equilibrium Chlorine Atom Transfer Process and Its Potential for Assessment of Steric Pressure by Bulky Aryls
作者:Rhett C. Smith、Shashin Shah、Eugenijus Urnezius、John D. Protasiewicz
DOI:10.1021/ja028422r
日期:2003.1.1
An unusually facile intermolecular chlorine atom transfer process has been discovered between the phospha-Wittig reagents ArP=PMe3 and ArPCl2 (Ar is a sterically hindered aryl group). The atom transfer process is catalyzed by added PMe3. A mechanism is forwarded that is based upon a Me3P/Me3PCl2 couple that allows shuttling of chlorine atoms between ArP groups. This unique transfer process is exploited to evaluate the steric properties of aryl groups via an equilibrium process.
Three Different Fates for Phosphinidenes Generated by Photocleavage of Phospha-Wittig Reagents ArPPMe<sub>3</sub>
作者:Shashin Shah、M. Cather Simpson、Rhett C. Smith、John D. Protasiewicz