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The Norrish type I reaction is the photochemical cleavage or homolysis of aldehydes and ketones into two free radical intermediates (α-scission). The carbonyl group accepts a photon and is excited to a photochemical singlet state. Through intersystem crossing the triplet state can be obtained.
Later, Bucherer and Lieb found that 50% alcohol was an effective solvent for the reaction. With this solvent, aldehydes reacted well, and ketones gave excellent yields. In 1934 Bucherer and Steiner proposed a mechanism for the reaction. While there were some issues with the mechanism, it was mostly accurate. [5]
The Paternò–Büchi reaction, named after Emanuele Paternò and George Büchi, who established its basic utility and form, [1] [2] is a photochemical reaction, specifically a 2+2 photocycloaddition, which forms four-membered oxetane rings from an excited carbonyl and reacting with an alkene.
The Buchner–Curtius–Schlotterbeck reaction is the reaction of aldehydes or ketones with aliphatic diazoalkanes to form homologated ketones. [1] It was first described by Eduard Buchner and Theodor Curtius in 1885 [2] and later by Fritz Schlotterbeck in 1907. [3]
The Dakin oxidation. The Dakin oxidation (or Dakin reaction) is an organic redox reaction in which an ortho- or para-hydroxylated phenyl aldehyde (2-hydroxybenzaldehyde or 4-hydroxybenzaldehyde) or ketone reacts with hydrogen peroxide (H 2 O 2) in base to form a benzenediol and a carboxylate.
The Sarett oxidation is an organic reaction that oxidizes primary and secondary alcohols to aldehydes and ketones, respectively, using chromium trioxide and pyridine.Unlike the similar Jones oxidation, the Sarett oxidation will not further oxidize primary alcohols to their carboxylic acid form, neither will it affect carbon-carbon double bonds. [1]
The Parikh–Doering oxidation is an oxidation reaction that transforms primary and secondary alcohols into aldehydes and ketones, respectively. [1] The procedure uses dimethyl sulfoxide (DMSO) as the oxidant and the solvent, activated by the sulfur trioxide pyridine complex (SO 3 •C 5 H 5 N) in the presence of triethylamine or diisopropylethylamine as base.
Aldol reactions may proceed by two distinct mechanisms. Carbonyl compounds, such as aldehydes and ketones, can be converted to enols or enol ethers. These species, being nucleophilic at the α-carbon, can attack especially reactive protonated carbonyls such as protonated aldehydes. This is the 'enol mechanism'.