Ag. Martinez et al., ENANTIOSPECIFIC SYNTHESIS OF SUBSTITUTED BICYCLO[2.1.1]HEXANE-1-CARBOXYLIC ACIDS AND ESTERS, Tetrahedron : asymmetry, 4(11), 1993, pp. 2333-2334
The base promoted ring contraction of the readily accessible homochira
l 2-oxo-1-norbornyl triflates 3 in 60% ethanol takes place with format
ion of bicyclo[2.1.1]hexane (4a), (+)- or (-)-7,7-dimethyl-bicyclo[2.1
.1]hexan-1-carboxylic acids (4c or 4b) and the corresponding ethyl est
ers in good yields.