The p-tosylhydrazones of conjugated carbonyl compounds are not deoxygenated by NaBH4 in methanol, but undergo an alkaline decomposition to diazoalkenes. The partition of the diazo compound between the solvolysis and intramolecular 1, 3-dipolar cycloaddition processes depends on the degree and type of substitution at the fl position. The use of base (NaBH4, NaOR, or KzC03) in alcoholic solvents provides a mild, convenient, and high- ...
