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A halogen addition reaction is a simple organic reaction where a halogen molecule is added to the carbon–carbon double bond of an alkene functional group. [1] The general chemical formula of the halogen addition reaction is: C=C + X 2 → X−C−C−X (X represents the halogens bromine or chlorine, and in this case, a solvent could be CH 2 ...
Such reactions give alkenes in the case of vicinal alkyl dihalides: [2] R 2 C(X)C(X)R 2 + M → R 2 C=CR 2 + MX 2. Most desirable from the perspective of remediation are dehalogenations by hydrogenolysis, i.e. the replacement of a C−X bond by a C−H bond. Such reactions are amenable to catalysis: R−X + H 2 → R−H + HX
Dihydroxylation is the process by which an alkene is converted into a vicinal diol. Although there are many routes to accomplish this oxidation, the most common and direct processes use a high-oxidation-state transition metal (typically osmium or manganese). The metal is often used as a catalyst, with some other stoichiometric oxidant present. [1]
Vicinal difunctionalization refers to a chemical reaction involving transformations at two adjacent centers (most commonly carbons). This transformation can be accomplished in α,β-unsaturated carbonyl compounds via the conjugate addition of a nucleophile to the β-position followed by trapping of the resulting enolate with an electrophile at the α-position.
The Milas hydroxylation is an organic reaction converting an alkene to a vicinal diol, and was developed by Nicholas A. Milas in the 1930s. [1] [2] The cis-diol is formed by reaction of alkenes with hydrogen peroxide and either ultraviolet light or a catalytic osmium tetroxide, [3] vanadium pentoxide, or chromium trioxide.
In 1 H-NMR spectroscopy, the coupling of two hydrogen atoms on adjacent carbon atoms is called vicinal coupling. The coupling constant 3 J represents coupling of vicinal hydrogen atoms because they couple through three bonds. Depending on the other substituents, the vicinal coupling constant is typically a value between 0 and +20 Hz. [2]
The Upjohn dihydroxylation is an organic reaction which converts an alkene to a cis vicinal diol. It was developed by V. VanRheenen, R. C. Kelly and D. Y. Cha of the Upjohn Company in 1976. [1] It is a catalytic system using N-methylmorpholine N-oxide (NMO) as stoichiometric re-oxidant for the osmium tetroxide. It is superior to previous ...
The reaction has been applied to alkenes of virtually every substitution, often high enantioselectivities are realized, with the chiral outcome controlled by the choice of dihydroquinidine (DHQD) vs dihydroquinine (DHQ) as the ligand. Asymmetric dihydroxylation reactions are also highly site selective, providing products derived from reaction ...