- Reaction of the ketone or aldehyde with hydrazine yields a hydrazone in the normal way.
- Base then abstracts one of the weakly acidic protone from -NH2, yielding a hydrazone anion. This anion has an "allylic" resonance from that places the negative charge on carbon and the double bond between nitrogens.
- Protonation of the hydrazone anion takes place on carbon to yield a neutral intermediate.
- Base-induced loss of nitrogen then gives a carbanion...
...that is protonated to yield neutral alkane product.