A convenient one-pot approach to the preparation of α-diazo-β-ketosulfones from sulfonyl
chlorides is described. It involves the conversion of the sulfonyl chloride to sodium
sulfinate, alkylation of the latter with α-haloketones followed by diazo transfer
using the ‘sulfonyl-azide-free’ (‘SAFE’) protocol in aqueous medium. The simple and
expedient method relies on readily available starting materials and provides facile
access to a wide variety of valuable diazo reagents for organic synthesis.
Key words
aliphatic diazo compounds - diazo ketosulfones - diazo transfer - α-haloketones -
Rh(II)-catalyzed cyclization - pyrazole synthesis