Thermodynamic Stability and Reactivity of Silylated Bis(oxy)iminium Ions
作者:Yulia A. Khomutova、Vladimir O. Smirnov、Herbert Mayr、Sema L. Ioffe
DOI:10.1021/jo070633x
日期:2007.11.1
trialkylsilyl triflates was investigated by applying NMR techniques. In several cases, a flexible nitronate−bis(oxy)iminium ion (as an ion pair with triflate as counterion) equlibrium was found, and its thermodynamic parameters were determined. Elevation of temperature or dilution shifts this equilibrium toward the reactants. Activation parameters for the C,C-coupling reaction of silylated bis(oxy)iminium ions
New C−C Coupling Reaction of Cyclic Nitronates with Carbon Nucleophiles. Umpolung of the Conventional Reactivity of Nitronates
作者:Vladimir O. Smirnov、Sema L. Ioffe、Alexander A. Tishkov、Yulia A. Khomutova、Ivan D. Nesterov、Michael Yu. Antipin、William A. Smit、Vladimir A. Tartakovsky
DOI:10.1021/jo048944k
日期:2004.11.1
Cyclic six-membered nitronates 1 are involved in diastereoselective C−Ccoupling reactions with various nucleophiles in the presence of either catalytic or stoichiometric amounts of TBDMSOTf to give the previously unknown N-siloxytetrahydrooxazines. The intermediacy of N,N-bis(oxy)iminium cations was proven by NMR data.