The Magnetic Optical Rotation of Carbonyl Compounds

Recently McCaffery et al. examined the magnetic optical activity of several ketones and stated that the n → π* transition of almost all the compounds studied showed no magnetic c.d. These results contrast with earlier measurements of magnetic o.r.d. by Shashoua and Briat, who in some of these compounds observed the presence of A terms, which are larger by a factor of 100 than the limit of sensitivity of McCaffery's apparatus. McCaffery et al. have therefore expressed doubts concerning the accuracy of Shashoua and Briat's experimental findings.