Styrene oxide deoxygenation

The deoxygenation of styrene oxide with dichlorocarbene exhibits a normal 13C isotope effect of 1.016 for the -carbon of the styrene oxide and an inverse isotope... 

Another example of coarctate reaction studied by means of 13C KIEs is the deoxygenation of styrene oxide 51 with dichlorocarbene.95... 

Hydrogenolysis of styrene oxide in ethanol affords not 1-phenylethanol but always 2-phenylethanol, together with deoxygenated products and phenyl acetaldehyde (eq. 13.13). The hydrocarbon formed at the initial stages over Raney Ni was found to be... 

Wittig and Haag " found that styrene oxide on being heated with triphenylphosphine to 165° is deoxygenated to styrene in yield of about 50%. The reaction acquires preparative interest as applied to epoxides not available from olefins such as the /8-phenylglycidic ester (1) obtained by the Darzens condensation. Heated with an... 

Chromium(II) reagents have been used for the deoxygenation of styrene oxide and cyclohexene oxide [36]. The first step of this transformation is thought to be epoxide opening via electron transfer yielding a 6-chromiumoxy radical that is trapped by a second equivalent of chromium(II). Elimination of a chromium oxo species completes the reaction as shown in Scheme 19. 

The participation of (3-metaloxy metal species in this context was first discussed by Kochi, Singleton, and Andrews in 1968 [7] in relation to their deoxygenation of styrene and cyclohexene oxide by chromium(II) reagents, as shown in Scheme 12.2. 

Nair et al. (2001) describe the bromination of alkenes using a mixture of ammonium hexanitratocerate(IV) and potassium bromide in a two-phase system consisting of water and dichloromethane. For instance, styrene is transformed by this reaction system in excellent yield at room temperature into 1,2-dibromo-phenyl ethane (scheme 28). It is assumed that the bromide ion is first oxidized by CAN to the bromine radical, which subsequently undergoes addition to the double bond to produce a benzylic radical. Trapping of another bromine radical results in the formation of the 1,2-dibromide. The method is not only applicable to substituted styrenes, but also to alkenes and o, 5-unsubstituted carbonyl compounds. However, the choice of the solvent is of prime importance the reaction only occurs in the water/dichloromethane two-phase system. In other solvents, like aqueous solutions of methanol or acetonitrile, a variety of products such as phenacyl bromides and nitratobromides are formed (scheme 29). The nitrato bromides are formed exclusively when the reaction is carried out in a deoxygenated atmosphere. In the two-phase system water/dichloromethane, side reactions are avoided be-... 

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