The Pschorr reaction is a classic name reaction in organic chemistry, named after the German chemist Robert Pschorr. It involves the copper-salt-promoted decomposition of aromatic diazonium salts to generate aryl radicals, which subsequently undergo intramolecular aryl-aryl coupling to construct biaryl or fused polycyclic aromatic systems. This reaction is particularly efficient for...
15
Mar
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...
15
Mar
In three distinct steps, the Robinson annulation converts a ketone and an α,β-unsaturated ketone into a substituted cyclohexenone compound. First, the base creates an enolate ion intermediate, which reacts with the α,β-unsaturated ketone in a conjugate 1,4 addition (Michael reaction) to form a 1,5 diketone. An intramolecular aldol reaction occurs...
29
Dec
The Gewald reaction refers to the condensation of ketones or aldehydes with α-cyanoesters in the presence of elemental sulfur to yield polysubstituted 2-aminothiophene derivatives. Discovered and named after the German chemist Karl Gewald, it is a significant method for constructing polysubstituted 2-aminothiophenes. This reaction enables the efficient one-step synthesis of...
29
Dec
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...
10
Dec
A benzyl protecting group is often used to protect alcohols in synthetic reactions. Benzyl groups are usually introduced via the Williamson SN2 reaction, requiring a benzyl halide, a base and a solvent such as DMF. Lab Tips: Benzyl protection can also be achieved under non basic conditions (via the...
