Benzyne epoxidation

The decarboxylation of diazotized anthranilic acid carried out by Stiles and Miller49 is also a fragmentation reaction it affords dehydrobenzene (benzyne), which reacts at once as a dienophile with, e.g., furan, giving 1-naphthol by way of an epoxide. 

Some of the important click reactions are (Kolb and Sharpless 2003 Adzima and Bowman 2012) azide-alkyne azide-sulfonyl cyanide benzyne-azide cycloaddition and hetero Diels-Alder reactions nucleophilic ring opening of strained molecules such as epoxides, aziridines, etc. non-aldol-type reactions and additions to carbon-carbon multiple bonds through oxidation-type reactions such as epoxidation, hydrox-ylation, etc. For more details, the reader is referred to a recent review by Adzima and Bowman (2012). 

The generated phosphide boranes are extremely nucleophilic and reacted smoothly with activated alkyl halides (entries 3-7), epoxides (entries 1, 2 and 8) and molecules with activated multiple bonds such as ethyl acrylate (entry 9), benzyne (10) or even fullerene (entry 14). Some C2-symmetric diphosphine... 

To the more usual homolytic fragmentation of aryl halides (from the excited state or from the radical anion, the well known SrnI reaction, for a recent example see the arylation of aromatics), the heterolytic version of the reaction which produces phenyl cations has more recently joined. A theroretic study on the photodissociation of fluorinated iodobenzenes has been published. The perfluoroallgrlation of various alkenes has been obtained by irradiation in the presence of iodoperfluorobutane. The formation of phenyl cations is exemplified in many arylation reactions and, in the case of o-chlorostannane, also a benzyne has been reported. In the field of polymer chemistry, iodonium salts are model cationic photoinitiators. In particular the truxene-acridine/diphenyl iodonium salt/9-vinylcarbazole combination is able to promote the ringopening polymerization of an epoxide, whereas the truxene AD/allq l halide/amine system is very efficient in initiating the radical photopolymerization of an acrylate. ... 

S. Beltran-Rodil, D. Pena, E. Guitian, Reaction of benzyne with styrene oxide insertion of arynes into a C-O bond of epoxides, Synlett 8 (2007) 1308-1310. 

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