Barriers to internal rotation in neopentylbenzenes substituted on the benzyl group. A13C NMR band shape study
作者:Sven Andersson、Torbjörn Drakenberg
DOI:10.1002/omr.1270211206
日期:1983.12
AbstractTwo series of neopentylbenzenes with one or two substituents on the benzyl group have been synthesized. In one series the substituents were H, F, Cl, Br, I, OCH3, OCOCH3, OSi(CH3)3 CH3 and CH2CH3, and in the other OH and R [R H, CH3, CH2CH3, (CH2)3CH3, CH(CH3)2 and C(CH3)3]. Barriers to internal CC and CC rotation have been estimated by 13C NMR band shape methods. Estimated barriers were found to increase as the size of the substituent increases. The results are discussed in terms of possible initial and transition states, based on summations of results from molecular mechanics (MM) calculations, using the Allinger MMP1 program. Barriers estimated experimentally are compared with results from other systems found in the literature.