Method of producing 6,6-dimethyl-3-oxabicyclo[3.1.0]hexan-2-one

1 2 2 1 2 A method of producing 6,6-dimethyl-3 -oxabicyclo [3.1.0]hexan-2-one comprising subjecting a cyclopropane compound of the formula (1): (wherein, Rrepresents an alkyl group, Rrepresents an alkyl group having carbon atom(s) of 1 to 10, a haloalkyl group having carbon atom(s) of 1 to 10, or an aryl group having carbon atoms of 6 to 10 optionally substituted by an alkyl group having carbon atom(s) of 1 to 10, and when Rrepresents the alkyl group, Rand Rare optionally the same or different each other.) to any of the following reactions a), b) and c):