The rate-accelerating effects of fluoroalcohol solvents for generating trivalent hypervalent iodine species and the conversion into diaryliodonium(iii) salts have been used for the first time to realize a facile and clean one-pot synthesis of diaryliodonium(iii) salts 3 from aryl iodides 1 and suitable arene partners 2 with peracetic acid (PAA). The use of PAA as a green and practical oxidant is significantly effective in fluoroalcohol solvents. The scope and limitations of the methodology are elucidated by investigation of a wide variety of representative substrates.
Synthesis of N,N′-Di-Boc-2H-isoindole-2-carboxamidine, the first representative of isoindoles containing guanidine functionality, was carried out. The cycloaddition reactivity of this new Diels–Alder heterodiene was studied and the title compound was employed as a cycloaddition delivery reagent for guanidine functionality. Higher reactivity was found in comparison with the corresponding pyrrole derivative. Substitution with fluorine or guanidine functionality does not change the reactivities of isoindoles, and these findings are in good accord with computational results.