Kinetics and Mechanism of the Addition of Benzylamines to ¥á-Cyano-¥â-phenylacrylamides in Acetonitrile

Bulletin of the Korean chemical society

Myoung Hwa Ku¹  Hai Whang Lee¹  Hyuck Keun Oh¹ 

关键词: Nucleophilic addition reaction;    Single-step process;    Cross-interaction constant;    Kinetic isotope effect;    Four-center cyclic transition state;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

Nucleophilic addition reactions of benzylamines (BA; XC₆H₄CH₂NH₂) to �?-cyano-�?-phenylacrylamides (CPA; YC₆H₄CH=C(CN)CONH₂) have been investigated in acetonitrile at 25.0 ^oC. The rate is first order with respect to BA and CPA and no base catalysis is observed. The addition of BA to CPA occurs in a single step in which the addition of BA to C�? of CPA and proton transfer from BA to C�? of CPA take place concurrently with a four-membered cyclic transition state structure. The magnitude of the Hammett (ヱX) and Bronsted (モX) coefficients are rather small suggesting an early tansition state (TS). The sign and magnitude of the crossinteraction constant, ヱXY (= -0.26), is comparable to those found in the normal bond formation processes in the S_N2 and addition reactions. The normal kinetic isotope effect (kH/kD > 1.0) and relatively low ツH× and large negative ツS× values are also consistent with the mechanism proposed.

【 授权许可】

Unknown