is more pronounced thanThe dipolar resonance form of diphenylcyclopropenone has aromatic character. Its stabilityleads to increased charge separation and a larger dipole moment.(d)Decreased electron density at the bcarbon atom of an a,b-unsaturated ketone is responsiblefor its decreased shielding. The decreased electron density arises from the polarization of itspelectrons as represented by a signifcant contribution of the dipolar resonance form.18.39Bromination can occur at either of the two a-carbon atoms.The1H NMR spectrum of the major product, compoundA, is consistent with the structure of 1-bromo-3-methyl-2-butanone. The minor product B is identifed as 3-bromo-3-methyl-2-butanone on thebasis of its NMR spectrum.18.40Three dibromination products are possible from ahalogenation of 2-butanone.The product is 1,3-dibromo-2-butanone,on the basis of its observed 1H NMR spectrum, whichshowed two signals at low
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This note was uploaded on 09/30/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.