Intermolecular [2 + 2] cycloaddition reaction of an allenyl silyl ether with vinyl ethers was realized on the basis of electrophilic activation of the allene by the platinum–phosphine catalyst, affording the corresponding methylenecyclobutanes in good yield. The use of the bulky trialkynylphosphine as a ligand was indispensable to achieve highly selective [2 + 2] cycloaddition.
Oxycyanation of Vinyl Ethers with 2,2,6,6-Tetramethyl-<i>N</i>-oxopiperidinium Enabled by Electron Donor–Acceptor Complex
作者:Jia-Li Liu、Ze-Fan Zhu、Feng Liu
DOI:10.1021/acs.orglett.7b03858
日期:2018.2.2
An efficient and mild oxycyanation of vinyl ethers with 2,2,6,6-tetramethyl-N-oxopiperidinium and TMSCN is described. The mechanistic studies indicated that the formation of an electrondonor–acceptorcomplex and subsequent single-electron-transfer process could be involved in the reaction.
A Pt(II)-catalyzed [3 + 2] cycloaddition reaction of silyl propadienyl ethers and alkenyl ethers has been developed as the first example of the utilization of allenes as a three-carbon unit in a transition-metal-catalyzed intermolecularcycloaddition reaction. Pt(II)-containing 1,3-dipole equivalents generated by electrophilic activation of silyl propadienyl ethers using a Pt(II) catalyst reacted with
Kinetics of bromination of highly reactive .alpha.-methoxystyrenes. The balance between thermodynamic and intrinsic kinetic contributions to the selectivity in bromination and protonation of styrenes
作者:Marie Francoise Ruasse、Jacques Emile Dubois
DOI:10.1021/ja00323a028
日期:1984.5
des composes X-C 6 H 4 -C(OMe)=CH 2 (X=OMe −4 , Me −4 , H, F −4 , Cl −3 , CF 3−3 , NO 2−3 , NO 2−4 ) sont mesures afin d'evaluer le changement de selectivite avec les additions electrophiles sur les styrenes
Les effet des substituants du cycle dans les bromations des composes XC 6 H 4 -C(OMe)=CH 2 (X=OMe -4 , Me -4 , H, F -4 , Cl -3 , CF 3-3 , NO 2−3 , NO 2−4 ) 子测量 afin d'evaluer le changement de selectivite avec les 添加亲电试剂 sur les 苯乙烯
Structure−Reactivity Effects on Primary Deuterium Isotope Effects on Protonation of Ring-Substituted α-Methoxystyrenes
作者:Wing-Yin Tsang、John P. Richard
DOI:10.1021/ja905080e
日期:2009.10.7
Primary product isotopeeffects (PIEs) on L(+) and carboxylic acid catalyzed protonation of ring-substituted alpha-methoxystyrenes (X-1) to form oxocarbenium ions X-2(+) in 50/50 (v/v) HOH/DOD were calculated from the yields of the alpha-CH(3) and alpha-CH(2)D labeled ketone products, determined by (1)H NMR. A plot of PIE against reaction driving force shows a maximum PIE of 8.7 for protonation of