Bromoiodinanes with an I(iii)–Br bond: preparation, X-ray crystallography and reactivity as electrophilic brominating agents

Abstract

Bromoiodinanes--conveniently and directly prepared from iodobenzenecarbinols and N-bromosuccinimide, and characterised for the first time crystallographically--act as electrophilic bromine donors.

Bis(guanidinium) tris(pyridine-2,6-dicarboxylato-κ3O2,N,O6)zirconate(II) tetrahydrate

“…The two I-O bonds observed measure 2.022 (3) Å and 2.017 (3) Å, respectively. These are shorter than the corresponding I-O bonds found in the chloro (2.042 (2) Å) (Amey & Martin, 1979;Niedermann et al, 2010) and bromo (2.050 (5) Å) (Braddock et al, 2006) analogs. This is consistent with the trans effect behavior described in a variety of hypervalent λ 3 -iodane compounds (Ochiai et al, 2006).…”

“…For the synthesis and structural analysis of the bromo analog of the title compound, see: Braddock et al (2006). For the synthesis and structural analysis of the chloro analog of the title compound, see: Amey & Martin (1979); Niedermann et al (2010).…”

Oxidative Heterocycle Formation Using Hypervalent Iodine(III) Reagents

“…The reaction was proposed to occur via the intermediacy of an iodonium ion which, after its formation, gets intercepted by the pendant carboxylate ion. Thereafter, several examples of such reactions of unsaturated compounds using different hypervalent iodine(III) reagents have been reported [50][51][52]. In recent years, chiral hypervalent iodine(III) reagents have received immense attention and have been applied extensively in the stereoselective synthesis of heterocycles.…”

Electrophilic fluorination using a hypervalent iodine reagent derived from fluoride

“…Our synthetic strategy was to introduce a good leaving group onto the hypervalent iodine 30 reagent in order to facilitate nucleophilic displacement by fluoride (Scheme 3). To this end, the new hypervalent iodine reagents, trifluoroacetoxyiodane 9 and tosyliodane 10, were synthesised by the reaction of 2-(2-iodophenyl)propan-2-ol 1 with either PhI(OCOCF 3 ) 2 or PhI(OH)(OTs) following Koser's 35 procedure 12 and the solid-state structures of both compounds are presented in the supplementary information. When the trifluoroacetoxyiodane 9 was reacted with 1.2 equivalents of TBAF in dichloromethane, a mixture of the fluoroiodane 8 and the hydroxyiodane 7 was obtained in a 3:1 ratio.…”

“…1 An alternative, non-metal based strategy could be envisaged using cyclic hypervalent iodine(III) 15 compounds which have been shown to be mild, non-toxic and selective reagents for halogenation. [2][3][4] These reagents are normally prepared by oxidation of iodine(I) species with electrophilic reagents such as tert-butyl hypochlorite (1 → 3) and N-bromosuccinimide (1 → 2), 2 Our research group is interested in designing new methods for introducing fluorine into organic molecules 5 because of the importance of incorporating fluorine into drug candidate 35 molecules. 6 Since Banks first reported SelectFluor in 1992, 7 the fluoraza reagents have become increasingly popular electrophilic fluorinating reagents because they are commercially-available, shelf-stable powders that can be used to fluorinate a wide variety of substrates.…”