From halohydrins

The formation of vicinal halohydrins from alkenes was described in Section 6.17. Halohydrins are readily converted to epoxides on treatment with base ... 

Table 9. CPO-catalyzed formation of halohydrins from olefins ...

Formation of Halohydrins from Epoxides (3) OC-seco-Halo-de-alkoxylation... 

No attempt will be made here to cite every recorded instance of the preparation of a halohydrin from an olefin. It will be sufficient to consider (1) the various moans employed to generate hypohakuw acids (2) the mechanism of the reaction and (3) a few representative examples of its application. 

This problem is similar to the one in part d) in that it requires the preparation of a halohydrin from an aUcyl halide. The strategy is the same. Convert the alkyl halide to an alkene, and then form the halohydrin by treatment with the appropriate halogen in aqueous solution. 

Hydrazones have been cyclized with 10 to yield pyrazole derivatives . Hydrazines reacted with 10 and orthoformates to produce pyrazole derivatives 33 Tosylazides gave triazolecarbonitrile 34. Furan derivatives have been prepared by reactions of 10 with halohydrines, from 10, furoin and diethylamine. Reaction of 10 with D-ribose in the presence of ZnCh gave furan derivative 35. ... 

X = Cl. Br. T Treatment of polystyryl diphenylphosphine with CL, Br, or I, in CH,CL.24 Halohydrins from epoxides yields and selectivities compare well with those obtained with monomeric triphenyl phosphine-halogen complexes.2 11 Open and cyclic acetals and thioacetals by treatment of aldehydes and ketones with alcohols or thiols in the presence of polystyryl diphenylphosphine iodine complex.249... 

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