Hypervalent Iodine–Mediated Ring Contraction Reactions

Abstract

Hypervalent iodine reagents constitute a powerful tool in modern synthetic organic chemistry, promoting several important reactions. One such reaction is the ring contraction of cycloalkenes and cycloalkanones promoted by iodine(III) compounds, such as iodobenzene diacetate, iodosylbenzene, iodotoluene difluoride, and [hydroxy(tosyloxy)-iodo]benzene (Koser´s reagent). This review covers all the literature related to the ring contraction of cyclic ketones and olefins promoted by iodine(III) species.

Chemistry of Polyvalent Iodine

“…Numerous reviews on specific classes of polyvalent iodine compounds and their synthetic applications have recently been published 18–61. Most notable are the specialized reviews on [hydroxy(tosyloxy)iodo]benzene,41 the chemistry and synthetic applications of iodonium salts,29,36,38,42,43,46,47,54,55 the chemistry of iodonium ylides,56–58 the chemistry of iminoiodanes,28 hypervalent iodine fluorides,27 electrophilic perfluoroalkylations,44 perfluoroorgano hypervalent iodine compounds,61 the chemistry of benziodoxoles,24,45 polymer-supported hypervalent iodine reagents,30 hypervalent iodine-mediated ring contraction reactions,21 application of hypervalent iodine in the synthesis of heterocycles,25,40 application of hypervalent iodine in the oxidation of phenolic compounds,32,34,50–53,60 oxidation of carbonyl compounds with organohypervalent iodine reagents,37 application of hypervalent iodine in (hetero)biaryl coupling reactions,31 phosphorolytic reactivity of o -iodosylcarboxylates,33 coordination of hypervalent iodine,19 transition metal catalyzed reactions of hypervalent iodine compounds,18 radical reactions of hypervalent iodine,35,39 stereoselective reactions of hypervalent iodine electrophiles,48 catalytic applications of organoiodine compounds,20,49 and synthetic applications of pentavalent iodine reagents 22,23,26,59…”

Study on the reactive transient α‐λ3‐iodanyl‐acetophenone complex in the iodine(III)/PhI(I) catalytic cycle of iodobenzene‐catalyzed α‐acetoxylation reaction of acetophenone by electrospray ionization tandem mass spectrometry

“…[5] In the past decade, efforts have been made to study the chemical reactivity and the oxidation mechanism of these hypervalent aryl iodine compounds. [1,2,8,9] These studies revealed the presence of some reactive hypervalent iodine species in the reaction solution. In 1995, Sam et al first used electrospray ionization mass spectrometry (ESI-MS) to study of oxidation reaction of PhIO in methanol [10] and they observed reactive l 3 [11] while Silva and co-workers studied the disproportionation reaction of DIB in acetonitrile and methanol by high-resolution ESI-MS/(MS).…”

An Unusual Ring‐Contraction/Rearrangement Sequence for Making Functionalized Di‐ and Triquinanes

“…[7] The ring contraction/ rearrangement reaction was found to be general and a series of structurally similar substituted 6-oxabicyclo[3.2.1]octan-8ones (10 b-k) furnished the corresponding 2,8-oxymethanobridged diquinanes 11 b-k in good yields upon reaction with BF 3 ·Et 2 O (2 equivalents; Scheme 4). Initial reaction of 10 a with p-TSA in benzene at reflux, to our surprise, furnished the 2,8-oxymethano-bridged diquinane 11 a in 55 % yield.…”