Heterocycles 2- phenyl triflate

Heteroarenes and Benzannulated Heterocycles. The heteroatom arylation methods involving 2-(trimethylsilyl)phenyl triflates have been extended to the preparation of heterocycles. Acridones, xanthones, and thioxanthones are readily obtained by reacting methyl 2-aminobenzoate, methyl salicylate, or methyl thiosalicylate, respectively, with the aryne generated from 2-(tri-methylsilyl)phenyl triflate (eq 8). The ar3me is also used to prepare various benzannulated heterocycles via a three-component coupling process where at least one other cort5)onent is an imine or carbonyl compound. This procedure provides simple entry to racemic substituted benzoitninofurans, 2-iminoisoindolines, ... 

A variety of five-membered nitrogen heterocycles can be prepared efficiently by inter- or intramolecular addition/cyclizations of sulfonamide anions with alkynyliodonium salts. The intermolecular variant employs the combination of the amides 172 or anilides 174 with propynyl(phenyl)iodonium triflate (Scheme 65) [131,132]. The yield of dihydropyrroles 173 in this cyclization is extremely sensitive to the nature of the protective group P the tosyl group in 172 proved... 

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