Wolff–Kishner reduction transforms a carbonyl group into a methylene group through deoxygenation by replacing the oxygen atom with two hydrogen atoms. The reaction is carried out at elevated temperatures, using a strong base and hydrazine. The reduction mechanism has two parts: Formation of hydrazone and elimination of nitrogen. The first part involves a multi-step condensation reaction between hydrazine and the carbonyl compound to form a hydrazone. In the second part, the base removes an N–H proton to generate the hydrazone anion, which resonance stabilizes to give a negative charge on the carbon atom. This deprotonation step is not easy and requires heat, necessitating the use of high-boiling solvents. The anion is reprotonated by water, followed by a second deprotonation of nitrogen, which drives the reaction forward by eliminating nitrogen gas and generating a carbanion. A final reprotonation on the carbanion gives an alkane.