Phenylselenium compounds

The use of free radicals allows great versatility and tolerance. Usually, the primary free radicals are generated by reaction of halides as well as phenyl-thio and phenylselenium compounds with stanna-nes such as nBu3SnH, silanes and germanes. Redox processes e.g. using Mnffl oxidation may also be employed. Since tin compounds are quite toxic there was a search going to use other methods for the generation of radicals. 

Full details are now available of Torssell s synthesis of l-desoxylycorin-7-one (15) (cf. Vol. 5, p. 172). ° Application of the phenylselenium bromide procedure to the lactam (12) led to an improved synthesis of the enol (13), which by acid-catalysed allylic rearrangement was converted into the allylic acetate (14) (Scheme 1) lycorine (16) has already been prepared from the latter compound. 

Finally, ultrasound has been used in the preparation of a variety of organoselenium and organotellurium compounds by reaction of alkyl halides, tosylates, mesylates and epoxides with the phenylselenium anion [107] and... 

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