Migration du groupe éthoxycarbonyle dans la transposition de <i>Wagner‐Meerwein</i>

Abstract

Ethoxycarbonyl group migration in the Wagner‐Meerwein rearrangement . 13 β‐Hydroxy‐esters have been treated with P 2 O 5 in benzene at 80°. Olefin‐forming dehydration, when possible, was found to be the main reaction. When this is excluded, tertiary or benzylic hydroxy‐esters react in a manner most easily explained by migration of the COOEt group, thus avoiding the formation of α‐carbonyl‐carbenium ions. On the other hand, in primary hydroxy‐esters (incapable of direct olefin formation), phenyl and methyl groups migrate in preference to COOEt, indicating in this case a concerted reaction.