O-Bromoiodobenzene

Distillation under reduced pressure gives o-bromoiodobenzene as a nearly colorless li< uid, b.p. 120 121°atl5 mm. Yield 65-75 g. (72 8.1%). 

By adding 10-20 ml. of the o-bromoiodobenzene solution to the metal bcfotc stirring is started, high local concentrations of... 

The photostimulated reaction of o-bromoiodobenzene with CH2COPh ions gives mo nosubstitution product 2 in 88% yield, which cyclizes to 2-phenylbenzofuran under catalysis by Cu (activated copper bronze) (Scheme 10.8) [19]. 

A flexible and convergent access to 2,3-disubstituted benzo[b]thiophenes has been developed (Scheme 22). The most concise approach involves a sequential coupling of an o-bromoiodobenzene with benzylthiol and zinc acetylides leading to the adduct 78. Treatment with iodine followed by an iodine/magnesium exchange and acylation provides the polyfunctional benzofuran derivatives. a... 

Formation of the tribenzoarsepin derivative involves thermolysis of a quaternary arsonium salt in a reaction similar to that which generates arsafiuorene derivatives [Eq. (86)]. As for the dibenzheterocycles, an organic dihalide provides the starting point for the synthesis. Reaction of o-bromoiodobenzene with magnesium in ether at 0°C followed by reaction with dimethyliodoarsine provides a disubstituted terphenyl derivative. Addition of 1,3-dibromopropane forms the cyclic quaternary salt (232) ... 

Benzyne precursors 1-Aminobenzotriazole. Benzenediazonium-2-carboxylate. Benzo-l,2,3-thiadiazole-l,l-dioxide. o-Bromofluorobenzene. o-Bromoiodobenzene. Diphenylio-donium-2-carboxylate monohydrate. 

In the flask is placed 150 ml. of anhydrous ether, and 5.7 g. (4.1 atomic equivalents) of lithium foil is then added (Note 1). A solution of 56.6 g. (0.2 mole) of o-bromoiodobenzene in 300 ml. of anhydrous ether is added dropwise (Note 2). When a vigorous reaction commences, the stirrer is started and the flask is cooled in ice water to maintain the temperature at about 10°. The reflux condenser is replaced by a thermometer, and the remainder of the o-bromoiodobenzene solution is added at a rate such that the temperature in the flask remains at about 10° (about 1.5 hours). When this addition is complete, 200 ml. of dry benzene is added the mixture is stirred at 10° for 1 hour and finally at room temperature for 1 hour. The mixture is then poured through a glass-wool filter on 200 g. of ice. 

Lithium ethoxide in condensation of benzaldehyde with triphenyldn-namylphosphonium chloride to form l,4-diphenyl-l,3-butadiene, 36 Lithium in formation of triphenylene from o-bromoiodobenzene, 106... 

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