Jan., 1940 RESTRICTED ROTATION IN ARYL OLEFINS ... [CONTRIBUTION FROM THE NOYES CHEMICAL LABORATORY, UNIVERSITY OF ILLINOIS] Restricted Rotation in Aryl Olefins. I. Preparation and Resolution of p-Chloro-fl- (2,4,6-trimethyl-3-bromophenyl)-~-methylacrylic ... Molecular dissymmetry due to restricted rota- tion between the ring and the olefinic carbon in appropriately substituted aryl olefins of types I and I1 was postulated in a previous ...