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

Abstract

Cyclopropane-1,2-diols are shown to undergo ring opening in acid to give, in most cases, α-ketols, formation of β-ketols occurring only rarely. The α-ketols are often accompanied by αβ-unsaturated ketones of the same carbon skeleton. Unsymmetrical diols open to give usually only one α-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.