Bridgehead–bridgehead 13C–13C coupling constant of a bicyclobutane
Abstract
The 13C n.m.r. spectrum of diethyl 1-methyl-3-phenylbicyclo[1,1,0]butane-2,4-dicarboxylate containing three 13C labels has provided a value of 5·4 Hz for the bridgehead–bridgehead 13C–13C coupling constant in agreement with theoretical predictions.