Abstract: cis-2-Phenyl-1-methylcyclopropanol undergoes a bimolecular electrophilic ring opening in acid solution leading to a 60: 40 mixture of 4-phenyl-2-butanone and 3-phenyl-2- butanone. Stereochemical studies on optically active substrate have shown that this SE~ reaction, the breaking of a carbon-carbon bond by a proton, proceeds with retention of configuration. In base the same cyclopropanol rapidly forms only 4-phenyl-2-butanone. ...
