The Grignard reaction is one of the most versatile methods for forming C–C bonds. Although the mechanism of action between Grignard reagents and carbonyl compounds is not yet fully understood, it is generally believed to proceed via either a "concerted mechanism" or a "radical mechanism." Experimental studies have shown that...

The Grubbs reaction is a method for achieving olefin metathesis using ruthenium (Ru) carbene catalysts (the Grubbs catalyst series), developed by Professor Robert H. Grubbs. Olefin metathesis was first discovered by accident in the 1950s. It refers to the process in which olefins, in the presence of metal carbene catalysts,...

The Hofmann rearrangement converts an amide into a primary amine with the loss of one carbon atom. First, a base deprotonates the amide. The deprotonated amide then attacks a halogen, forming an N‑haloamide. Subsequently, the N‑haloamide is deprotonated by base to give an N‑haloamide anion salt. This salt rapidly undergoes...

Hoffmann Elimination is a reaction in which an amine containing β-hydrogens is converted into an alkene under heating conditions, using iodomethane, water, and silver oxide. It is named after the German chemist August Wilhelm von Hofmann.The Hofmann elimination offers an efficient method for synthesizing alkenes from amines, especially when conventional...

The Pechmann condensation is a reaction in which phenols and β-keto esters react under acid catalysis to synthesize coumarin derivatives. It was first discovered by German chemist Hans Freiherr von Pechmann and is named after him. Coumarins are important intermediates in pharmaceuticals, agrochemicals, and functional materials. This reaction offers a...

The Ullmann reaction uses copper metal to convert aryl halides into biaryl compounds. It was first reported in 1901 by Fritz Ullmann and his student Bielecki, and is named after Fritz Ullmann. Although the reaction mechanism is not yet fully understood, two major pathways have been proposed. One is a...