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The volatile dioxiranes DMD and TFD can be isolated via distillation. Once isolated, dioxiranes can be kept in solutions of the corresponding ketones and dried with molecular sieves. These solutions are suitable when substrates or products are sensitive to hydrolysis. [17] Catalytic dioxirane oxidations do, however, require water.
Alkenes can be oxidized with ozone to form alcohols, aldehydes or ketones, or carboxylic acids.In a typical procedure, ozone is bubbled through a solution of the alkene in methanol at −78 °C (−108 °F; 195 K) until the solution takes on a characteristic blue color, which is due to unreacted ozone.
For small rings (fewer than eight atoms), a trans alkene cannot be achieved without substantial ring and angle strain (the p orbitals are improperly aligned for a π bond). Bredt's rule also applies to carbocations and, to a lesser degree, free radicals, because these intermediates also prefer a planar geometry with 120° angles and sp 2 ...
Jacobsen's catalysts R = Alkyl, O-alkyl, O-trialkyl Best Jacobsen catalyst: R = t Bu Katsuki's catalysts R 1 = Aryl, substituted aryl R 2 = Aryl, Alkyl. The Jacobsen epoxidation, sometimes also referred to as Jacobsen-Katsuki epoxidation is a chemical reaction which allows enantioselective epoxidation of unfunctionalized alkyl- and aryl- substituted alkenes.
Alkenes react with percarboxylic acids and even hydrogen peroxide to yield epoxides: RCH=CH 2 + RCO 3 H → RCHOCH 2 + RCO 2 H. For ethylene, the epoxidation is conducted on a very large scale industrially using oxygen in the presence of silver-based catalysts: C 2 H 4 + 1/ 2 O 2 → C 2 H 4 O. Alkenes react with ozone, leading to the scission ...
The Schenck ene reaction or the Schenk reaction is the reaction of singlet oxygen with alkenes to yield hydroperoxides. The hydroperoxides can be reduced to allylic alcohols or eliminate to form unsaturated carbonyl compounds. It is a type II photooxygenation reaction, and is discovered in 1944 by Günther Otto Schenck. [1]
The barrier for the rotation of the alkene about the M-centroid vector is a measure of the strength of the M-alkene pi-bond. Low symmetry complexes are suitable for analysis of these rotational barriers associated with the metal-ethene bond.In Cp Rh(C 2 H 4 )(C 2 F 4 ), the ethene ligand is observed to rotate with a barrier near 12 kcal/mol but ...
Selenoxide elimination (also called α-selenation) [1] is a method for the chemical synthesis of alkenes from selenoxides. It is most commonly used to synthesize α,β-unsaturated carbonyl compounds from the corresponding saturated analogues. [2] It is mechanistically related to the Cope reaction.