Methanolysis of 3,4-dihalogenochromans and 1,2-dihalogenotetralins

Abstract

Rates and activation parameters have been obtained for the methanolysis of trans-3eq,4eq-dihalogeno-2,2-dimethylchromans, trans-3ax,4ax-dihalogenochromans, and 1,2-dihalogenotetralins in methanol–acetone. The structures of the dihalogeno-compounds were deduced by n.m.r. measurements. The reactions involve a carbonium ion intermediate, the mechanism being dependent on steric and neighbouring-group effects. The results are similar to those for the hydrolysis of trans-3eq,4eq-dihalogeno-2,2-dimethylchromans.