Clemmensen reduction. Part 7. Acid-catalysed opening of cyclopropane-l,2-diols

Abstract

Cyclopropane-l,2-diols are shown to undergo ring opening in acid to give, in most cases, a-ketols, formation of (3-ketols occurring only rarely. The a-ketols are often accompanied by ap-unsaturated ketones of the same carbon skeleton. Unsymmetrical diols open to give usually only one a-ketol, the preference for the terminal group bonded to the carbonyl group being in the order methyl > phenyl > hydrogen. The relationship of these results to the Clemmensen reduction of 1.3-diketones is discussed.