Thermolysis of<i>N</i>-tetramethylpiperidinyl triphenylacetate: homolytic fragmentation of a TEMPO ester
作者:Huda Henry-Riyad、Thomas T. Tidwell
DOI:10.1002/poc.655
日期:2003.8
Thermolysis of N-tetramethylpiperidinyl triphenylacetate (7, Ph3CCO2T, T=2,2,6,6-tetramethylpiperidinyl) in benzene at 146°C leads to the formation of triphenylmethane (Ph3CH, 80%), tetramethylpiperidine (TH, 91%), and tetraphenylmethane (Ph4C, 9%). First-order rate constants for the decomposition at 132.8 and 150.0°C were 2.20 × 10−6 and 2.88 × 10−5 s−1, respectively. In benzene-d6 solvent the triphenylmethane
N-四甲基哌啶基三苯基乙酸酯(7,Ph 3 CCO 2 T,T = 2,2,6,6-四甲基哌啶基)在146°C的苯中热分解导致形成三苯基甲烷(Ph 3 CH,80%),四甲基哌啶( TH(91%)和四苯甲烷(Ph 4 C,9%)。在132.8℃和150.0℃下分解的一级速率常数分别为2.20×10 -6和2.88×10 -5 s -1。在苯-d 6溶剂中,三苯甲烷以Ph 3 CD的形式生成,其含量为20%(由1确定)。1 H NMR和质谱。结果被解释为表示博士3 CCO 2通过与形成的Ph协调一致两键断裂Ť经历热解3 Ç ⋅,四甲基自由基和CO 2。PH的形成4下用加入pH的发生3 Ç ⋅苯,随后从所得到的加合物的氢原子的抽象。使用DFT方法在B3LYP / 6-311 ++ G **水平计算被用来阐明HCO的键裂变2 T(2),并且表明裂解以HCO 2 ⋅和T ⋅由7.8千卡摩尔青睐-1相对于裂解HC(•)O和TO