What is pauson khand?

Pauson-Khand reaction is a chemical reaction that involves the cycloaddition of an alkyne, an alkene, and a metal carbonyl to form a cyclopentenone compound. The reaction was discovered by two chemists, Malcolm Pauson and Sir John K. D. Khand in 1976 and was named after them. It is an important reaction in organic chemistry and has utility in the synthesis of a variety of natural and synthetic compounds. The reaction mechanism involves the formation of a complex between the alkyne and the metal carbonyl, followed by cycloaddition with the alkene, resulting in the formation of a metal-complexed intermediate. This intermediate subsequently undergoes migratory insertion, beta-hydride elimination, and oxidative decarbonylation to generate the desired cyclopentenone product. The reaction is usually carried out under an inert gas atmosphere and at elevated temperatures.