Rearrangements of a cation of the neopentyl-type containing a diphenyl-phosphinyl substituent

Abstract

Deamination of 2-diphenylphosphinyl-2-methylpropylamine (4) and solvolysis of the 2-diphenylphosphinyl-2-methylpropyl toluene-p-sulphonate (9) lead to diphenylphosphinyl migration and products arising from the tertiary cation (15). The deamination also gives some of a product with a cyclopropane ring, but in no case is methyl migration observed. It is suggested that a protonated cyclopropyl intermediate is formed in the deamination. Rate studies on the tosylate suggest that the diphenylphosphinyl group participates in the rate-determining step and that it is ca. 70 times less effective than a methyl group at participation in this system.