AN ABNORMAL ALLYLIC SUBSTITUTION FOLLOWED BY A NOVEL ALLYLIC REARRANGEMENT

The products obtained from 2-halo-3-alkyl- and 3-±-chloroalkylbenzo [b] thiophene 1,1-dioxides with piperidine in benzene have been assigned structures using chemical methods combined with uv and nmr spectroscopy. Under these conditions 2-halo-3-alkylbenzo[b] thiophene 1,1-dioxides were found to undergo a tautomerism followed by a rapid abnormal allylic substitution. The 3-±-chloroethyl- and 3-(±-chloro-±-methylethyl)benzo[b] thiophene 1,1-dioxides were found to undergo an abnormal allylic substitution followed by an unusual ring opening and ring closing; the over-all result was molecular rearrangement. © 1968, American Chemical Society. All rights reserved.