Selenols aromatic compounds

This concept has been proofed for other compounds than phenols such as thiophenols/ selenols and also secondary aromatic amines. And indeed, an analogous reaction behavior has been found. FET ionization resulted in two products metastable radical cations and radicals corresponding to the dissociative cation structure. Furthermore, the concept is also working for compounds where instead of protons, another leaving group has been used as symbolized for the following... 

The direct selenoacetalization of carbonyl compounds by selenols is by far the shortest and most convenient route to selenoacetals. The reaction is usually carried out at 20 C with zinc chloride (0.5 equiv. versus the carbonyl con x>und) and delivers rapidly (<3 h) and in reasonably good yields methyl and phenyl selenoacetals derived from aliphatic aldehydes and ketones and cyclic ketones (Scheme 69). Selenoacetalization is more difficult to achieve with hindered ketones, such as adamantanone and diisopropyl ketone, and with hindered aromatic carbtmyl compounds. In these cases the reaction is best achieved with titanium tetrachloride instead of zinc chloride and is often limited to the methylseleno derivatives (Scheme 78). Tris(methylseleno)borane offers the advantage of not requiring an acid catalyst and is particularly useful for the selenoacetalization of acid labQe aldehydes such as citronellal (Scheme 70, e). 

Moreover, the selenol esters can acylate reactive arenes and heteroaromatic compounds when cop-per(I) triflate is employed as the selenophilic metal cation. - The acylation of aromatics by use of the benzene complex of copper(I) triflate (43 Scheme 12) was complete within an hour at room temperature, with benzene as solvent, and the acylation products were obtained in high yields. Intramolecular acylation was examined successfully, as shown in equation (20). 

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