Organic Chemistey for JEE|NEET|GATE|NET
Stevens rearrangement is a base-promoted [1,2]-migration rearrangement of quaternary ammonium salts or sulfonium salts to the corresponding tertiary amines or sulfides. Stevens rearrangement involves the [1,2]-migration of one of the groups on the nitrogen or sulfur atom.
The reaction is general for primary Nitronates, which yield aldehydes, and secondary ones, which pay ketones. And in fact, the first reported example involved nitroethane in forming acetaldehyde. Although this is essentially a degradative reaction and not a skeleton-building reaction, a reactivity aspect makes the Nef reaction extremely useful.
The Henry reaction was first reported by Belgian chemist Louis Henry in 1895. The Henry reaction involves the addition of a nitronate salt to a carbonyl compound, usually an aldehyde. The reaction is also referred to as a Nitroaldol reaction. It is C-C bond-forming reaction used in organic synthesis. Mechanism: The Henry Reaction Mechanism can present in two steps … Read more
The rearrangements reactions are important Name reaction in organic chemistry. Wittig rearrangement, first reported by G. Wittig and L. Löhmann in 1942, The Wittig rearrangement converts α-metalated ethers to metal alkoxides, yielding secondary or tertiary alcohols. Its nitrogen analog, the aza-Wittig rearrangement, transforms α-metalated tertiary amines into rearranged metal amides, producing homoallylic secondary amines. This … Read more
Sommelet-Hauser rearrangement is one of the thermal [2,3]-sigmatropic rearrangements, in which the benzylic quaternary ammonium salts are treated within the presence of a strong base like NaNH2, KNH2, as well as alkyl lithium to prepare the Substituted 3° benzylic amine.
The addition of aliphatic or aromatic aldehydes across activated double bonds in the presence of a nucleophilic catalyst for the synthesis of 1,4-diketones and γ-oxo nitriles is known as the Stetter reaction.