The gas-phase elimination kinetics of 2-arylethyl N,N-dimethylcarbamates, (CH3)2NCOOCH2CH2Ar, has been studied at the ab initio MP2/6-31G and MPW1PW91/6-31G(d,p) levels of theory. These carbamates produce N,N-dimethylcarbamic acid and the corresponding 4-substituted styrene in a rate determining step. The unstable intermediate N,N-dimethylcarbamic acid rapidly decarboxylate through a four-membered cyclic transition state to give dimethylamine . These calculations imply a concerted, non-synchronous six-membered cyclic transition state type of mechanism. The present results support the fact that the acidity of the benzylic hydrogen as an important factor for faster elimination rates.
Copyright 2007 Elsevier B.V., All rights reserved.
- Arylethyl N,N-dimethylcarbamates
- Gas-phase elimination
- MP2/6-31G and MPW1PW91/6-31G(d,p) calculations