Halogenation of a- to Carbonyl Groups

Halogenation of a- to Carbonyl Groups. Regioselective a-bromination or chlorination of unsymmetrical ketones at the more substituted -position has been demonstrated with trimethylsilyl halides in DMSO the halogenating species is presumed to be the 

The regioselective chlorination of unsymmetrical ketones at the more substituted -position has also been carried out using aqueous 

to produce organothallium (III) derivatives which then react 

Miscellaneous Methods. A paper describing directed catalytic steroid chlorination with a billion-fold turnover rate which was published during the year1 6 has since been retracted as the results have been found to be untenable, despite rigorous attempts to verify their validity prior to publication. The chemical community appreciates the speed with which Professor Breslow has publicly denied these results. The very significant achievements of his group in this area must not be overlooked by the chemical world simply because of the tortuous dishonesty of one research student. 

Benzyl ethers may be cleaved oxidatively to yield benzaldehyde 

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