Kinetic study of substituent effects on the mechanism of β-elimination of arenethiol from trans-2,3-bis(arylthio)-4-nitro-2,3-dihydrothiophenes in toluene
作者:Giovanni Petrillo、Marino Novi、Giacomo Garbarino、Carlo Dell'Erba
DOI:10.1039/p29850001741
日期:——
The 2,3-dihydrothiophene derivatives (1b–f) readily undergo, in toluene, regiospecific tributylamine-promoted syn-elimination of arenethiol to give the 2-(arylthio)-4-nitrothiophenes (2b–f). For the rather complex kinetic behaviour displayed by each member of the series, a rationalisation is proposed based on a stability of the substrate's conjugate base sufficient to allow formation of non-negligible
2,3-二氢噻吩衍生物(1b - f)在甲苯中容易进行区域特异性的三丁胺促进的槟榔酚合成消除,从而得到2-(芳硫基)-4-硝基噻吩(2b - f)。对于系列中每个成员显示的相当复杂的动力学行为,基于底物的共轭碱的稳定性提出了合理化建议,该稳定性足以允许沿着反应坐标形成不可忽略的中间离子对浓度。该系统可以得出有关离去基团驱除步骤的直接结论:可以假定在过渡态下碳与离去基团之间键断裂的高级程度。