Benziodoxole-Derived Organosulfonates: The Strongest Hypervalent Iodine Electrophiles and Oxidants

Abstract

This account describes the development of organosulfonyloxy-substituted iodine(III) and iodine(V) benziodoxole derived reagents, which are thermally stable compounds with useful reactivity patterns. Iodine(III) benziodoxoles and pseudobenziodoxoles are powerful electrophiles and mild oxidants toward various unsaturated compounds. In particular, pseudocyclic benziodoxole-derived triflate (IBA-OTf) is an efficient reagent for oxidative heteroannulation reactions. Aldoximes react with nitriles in the presence of IBA-OTf at room temperature to give 1,2,4-oxadiazoles in high yields. Moreover, IBA-triflate is used as a catalyst in oxidative heteroannulations with m-chloroperoxybenzoic acid as the terminal oxidant. The iodine(V) benziodoxole derived tosylates, DMP-tosylate and IBX-tosylate, are superior oxidants for the oxidation of structurally diverse, synthetically useful alcohols, utilized as key precursors in the total syntheses of polyketide antibiotics and terpenes. And finally, the most powerful hypervalent iodine(V) oxidant, 2-iodoxybenzoic acid ditriflate (IBX·2HOTf), is prepared by treatment of IBX with trifluoromethanesulfonic acid. According to the X-ray data, the I–OTf bonds in IBX-ditriflate have ionic character, leading to the high reactivity of this reagent in various oxidations. In particular, IBX-ditriflate can oxidize polyfluorinated primary alcohols, which are generally extremely resistant to oxidation.1 Introduction2 Iodine(III) Benziodoxole Based Organosulfonates3 Pseudocyclic Iodine(III) Benziodoxole Triflate (IBA-triflate)4 Pseudocyclic Iodine(III) Benziodoxole Tosylates5 Iodine(V) Benziodoxole Derived Tosylates6 Iodine(V) Benziodoxole Derived Triflate (IBX-ditriflate)7 Conclusions

Hypervalent iodine compounds: reagents of the future

“…[52][53][54][55]61,62 In general, radical and photochemical reactions of hypervalent iodine compounds belong now to one of the hottest areas of modern hypervalent iodine chemistry. 63,64 Numerous new, useful hypervalent iodine reagents have recently been developed, such as: the most powerful iodine(V) oxidants, 65 pseudocyclic hypervalent iodine reagents with improved physical properties and reactivity pattern, 66,67 benzyne precursors that are triggered by water at room temperature, 45 and watersoluble IBX derivatives. 68 The development of new synthetic methodologies and the use of hypervalent iodine reagents in specific classes of reactions have attracted significant research activity.…”

Hypervalent iodine chemistry and light: photochemical reactions involving hypervalent iodine chemistry

“…[5][6][7][8][9][10][11][12][13][14][15][16][17] Several hypervalent iodine reagents have been identified as potential oxidants. [18][19][20][21][22][23] Additionally, these reagents have been successfully applied to obtain several synthetic transformations including cyclizations, [24][25][26][27][28][29][30] aminations, [31][32][33][34] functionalizations of carbonyl compounds, [35][36][37][38] arylations, [39][40][41] atom-transfer reactions, 42 cycloaddition reactions, [43][44][45] and oxidative rearrangements. [46][47][48][49] Moreover, these reagents have been used as catalyst to develop number of organic transformations.…”