苄胺与苄叉-1,3-茚二酮在乙腈中加成反应的动力学及机理

Kinetics and mechanism of addition of benzylamines to benzylidene-1,3-indandiones in acetonitrile.

作者信息

Oh HK, Yang JH, Lee HW, Lee I

机构信息

Department of Chemistry, Chonbuk National University, Korea.

出版信息

J Org Chem. 2000 Aug 25;65(17):5391-5. doi: 10.1021/jo000512w.

DOI:10.1021/jo000512w

PMID:10993370

Abstract

Nucleophilic addition reactions of benzylamines (BA; XC6H4CH2NH2) to benzylidene-1,3-indandiones (BID; YC6H4CH=C(C=O)2C6H4) have been studied in acetonitrile at 25.0 degrees C. The rate is first-order with respect to BA and BID, and no base catalysis is observed. The structure-reactivity behaviors (k2, rhoX, betaX, and betaY) are intermediate between the two series of addition reactions of BA to beta-nitrostyrene (NS) and benzylidenemalononitrile (BMN) in acetonitrile. The normal kinetic isotope effects, kH/kD > 1.0, involving deuterated BAs (XC6H4CH2ND2) are smaller than those for the reactions of NS and BMN suggesting a somewhat looser bond formation in the transition state. The reaction is predicted to proceed in a single step with concurrent C(alpha)-N bond formation and proton transfer to C(beta). A hydrogen-bonded, four-center type cyclic transition state is proposed.

摘要

在25.0℃的乙腈中研究了苄胺（BA；XC6H4CH2NH2）与亚苄基-1,3-茚二酮（BID；YC6H4CH=C(C=O)2C6H4）的亲核加成反应。反应速率对BA和BID均为一级，未观察到碱催化作用。结构-反应活性行为（k2、rhoX、betaX和betaY）介于BA与β-硝基苯乙烯（NS）和苄叉丙二腈（BMN）在乙腈中的两组加成反应之间。涉及氘代BA（XC6H4CH2ND2）的正常动力学同位素效应kH/kD>1.0，比NS和BMN反应的同位素效应小，这表明过渡态中键的形成较为松散。预计该反应以单步进行，同时形成C(α)-N键并将质子转移至C(β)。提出了一种氢键连接的四中心型环状过渡态。