Bicyclo heptanol rearrangement

Tetramethylcyclohexanes.—An improved method for the preparation of j3-cyclocitral in purer form has been described. The methylsulphonate of a-cyclogeraniol (188) forms the cyclopropane derivative (189) with calcium carbonate, and this rearranges to a bicyclo[3,l,l]heptanol (190) with methane-sulphonic acid. Bohlmann and Zdero have found that the angelic acid ester of... 

Epoxybicyclo[3.2.0]heptanols 1 undergo acid-catalyzed cyclobutyl-cyclopropylmethyl rearrangement to form the bicyclo[4.1.0]hexan-3-one system 1. The efficiency of this cationic rearrangement appears to be dependent on the nature of the substituent R . This phenomenon is interpreted by the substituent effect on the stability of the incipient cyclopropylmethyl cation. 

If the rearrangement was performed in the presence of a reducing agent, such as potassium tri- erf-butoxyaluminum hydride, the intermediate ketone could be reduced to a 2 1 mixture of (la,2oi,6 )- and (la,2j6,6/S)-bicyclo[4.1.0]heptanols 6, which provided the first examples of a /ran -bicyclo[4.1.0]heptane. 

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