Etude des petits cycles—XXVIII : Regression de cycle generale de cyclobutanols—I. Halohydrines-1,2, diols-1,2 et epoxydes correspondants

Abstract

Methods for preparing 2-bromo and 2-tosyloxy cyclobutanols ( 1a and 1b) and 1,2-cyclobutanediols ( 6, 7, 8, 10 and 11), starting from 2-oxocyclobutanol 5 and 1,2-cyclobutanedione 9, have been studied. The cyclobutanols 1a and 1b undergo ring contraction in basic media while the 1,2-cyclobutanediols contract in acidic media or on heating. This ring contraction, reported previously for epoxycyclobutanes, affords cyclopropyl aldehydes or ketones in high yields.