Abstract
The earlier described ‘sulfonyl-azide-free’ (‘SAFE’) protocol for diazo transfer to
CH-acidic 1,3-dicarbonyl compounds (and their similarly activated congeners) has been
extended to the less reactive monocarbonyl substrates, which previously required a
separate activation step. Formylation in situ, followed by the addition of an optimized
amount of the ‘SAFE cocktail’ (obtained by mixing sodium azide, potassium carbonate,
and m-carboxybenzenesulfonyl chloride in water) led to the formation of the desired diazo
compounds, which were isolated by extraction in moderate to excellent yields, and,
in most cases, with no need for additional purification.
Key words
diazo transfer - water solubility - formylation - deformylation - C–H acidity
