Bicyclo hexan oxidative rearrangement

Bicyclo[2.2.0]hexan-2-ols oxidize with rearrangement to the isomeric bicyclo[2.1.1]hexan-2-ones. This takes place under (3ppenauer oxidation conditions, as well as with chromic acid, and is illustrated for photolevopimarate and chromic acid in equation (SI). The yield for this transformation is excellent, although the scope and synthetic potential are probably quite limited. The reaction is highly dependent on the nature the oxidant, as the chromate/pyridine reagent gave only 15% of the product after several days, and most of the starting alcohol was recovered. 

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