Hypervalent iodine compounds classes

The structure and reactivity of several specific classes of hypervalent iodine compounds have been investigated theoretically. Varvoglis, Tsipis and coauthors have studied the geometry and electronic stmcture of some hypervalent iodine compounds PhIX2 by means of extended Hlickel and CNDO/2 quantum chemical approaches [200], The bonding was analyzed in terms of both the model of delocalized MOs on the basis of interactions between fragment MOs derived from EHMO-SCCC calculations and that of localized MOs derived by the CNDO/2 method. The ability of these compounds to afford c -addition products with alkenes via a synchronous molecular addition mechanism was found to be theoretically feasible [200]. 

Another more environmentally friendly class of oxidants than chromium species involve hypervalent iodine compounds, such as the reagent commonly referred to as the Dess-Martin periodinane (DMP). Hypervalent means a compound with a greater electron count than predicted by the octet rule. The name DMP derives from the two chemists that developed its reactivity, and its use is called the Dess-Martin oxidation. Once again, primary alcohols are oxidized to aldehydes, while secondary alcohols are oxidized to ketones, and tertiary alcohols are unreactive. Hence, DMP performs the same transformations as PCC and the Swern oxidation (same products as in Example 10.11). 

The five-membered pentavalent iodine heterocycles represent a particularly important class of hypervalent iodine compounds. Cyclic iodine(V) compounds, such as IBX 212 and DMP 213, have found broad practical application as mild and selective reagents for the oxidation of alcohols and some other useful oxidative transformations. Several comprehensive reviews of the chemistry and synthetic applications of IBX and DMP have been published (2011JOC1185, 2006ARK26, 2010T7659, 2011AGE1524, 2001ACE2812). 

The purpose of present review is to summarize the application of different classes of iodine(III) compounds in carbon-carbon bond forming reactions. The first two sections of the review (Sects. 2 and 3) discuss the oxidative transformations induced by [bis(acyloxy)iodo] arenes, while Sects. 4 through 9 summarize the reactions of iodonium salts and ylides. A number of previous reviews and books on the chemistry of polyvalent iodine discuss the C-C bond forming reactions [1 -10]. Most notable is the 1990 review by Moriarty and Vaid devoted to carbon-carbon bond formation via hypervalent iodine oxidation [1]. In particular, this review covers earlier literature on cationic carbocyclizations, allyla-tion of aromatic compounds, coupling of /1-dicarbonyl compounds, and some other reactions of hypervalent iodine reagents. In the present review the emphasis is placed on the post 1990s literature. 

An explosive growth in the field of organic hypervalent iodine chemistry has been witnessed over the last few years. Several individual compounds and a variety of classes with many members have emerged as useful and sometimes unique reagents for a plethora of transformations, most of which are of considerable synthetic utility. 

This review is devoted to an overview of phenol dearomatization and its application in natural product synthesis through the use of a special class of phenolophile reagents that has attracted much attention in recent years, the hypervalent iodine reagents. These polyvalent iodine compounds, also called iodanes, are oxidizing electrophiles that can mediate a wide number of diverse chemical transformations not only of (hetero)aromatic compounds, but also of inter alia alkenes, alkynes, alcohols, sulfides, amines and amides, (enolizable) carbonyl... 

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