DoubleBond1Sigmabondand1Pibond
OMeAn X—ray structure determination of the phenyl compound 40 (R =B)established that (a) thealkene C=C bond adopts the Z—configuration and (b) the alkene and the ketene parts are sepa-rated by a pure C—C single bond (151 pm) and form a dihedral angle of 77° in the solid sta...