Kinetics and Mechanism of the Aminolysis of O-Methyl-S-Phenylthiocarbonates in Methanol

Bulletin of the Korean chemical society

Moon Ho Choi¹  In Sun Koo¹  Ho Bong Song¹  Ikchoon Lee¹  Hyuck Keun Oh¹ 

关键词: O-Methyl-S-phenylthiocarbonates;    Stepwise mechanism;    Zwitterionic tetrahedral intermediate;    Cross-interaction constant;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

Kinetic studies of the reaction of O-methyl-S-phenylthiocarbonates with benzylamines in methanol at 45.0 oC have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, T�?, with a hydrogen-bonded four-center type transition state (TS). These mechanistic conclusions are drawn based on (i) the large magnitude of rX and rZ, (ii) the normal kinetic isotope effects (kH/kD > 1.0) involving deuterated benzylamine nucleophiles, (iii) the positive sign of rXY and the larger magnitude of rXZ than that for normal SN2 processes, and lastly (iv) adherence to the reactivity-selectivity principle (RSP) in all cases.

【 授权许可】

Unknown