2-Naphthyl bromide

Figure 3.56. Scope of Pd/63-catalyzed as5mmetric Suzuki cross-coupling of naphthyl bromides with arylboronic acids.

Benzyl a-naphthyl selenide, (C6H5.CH2)Se(C10H7).2—This selenide is produced when the complex obtained from magnesium a-naphthyl bromide and metallic selenium is treated with benzyl chloride. It forms small colourless prisms from alcohol, M.pt. 68° to 69° C. It yields a picrate, which separates from ether in orange-red needles, M.pt. 118° C. 

Naphthyl bromide, AQ56 2-Naphthyl iodide, AQ6l... 

Of a number of metal salts tested, CoCl2, CuCl2, and (C6H5)2CuCl2 also effected coupling of model naphthyl bromides, but they are less effective than FeCl3. 

There are very numerous synthetic applications of the Heck reaction, notably in the coupling of naphthyl bromide with ethylene to give a precursor to naproxen 88... 

Di-a-naphthylchloroarsine, Ci(,H7)2AsCl, is preiiared by adding magnesimii a-naphthyl bromide to arsenious chloride. It melts at 166° to 167° C. With chlorine it yields di-a-uapktkylarsenic chloride, (CioH,) Cl8. 

Di-a-naphthylarsenoxide, (CioH7)aAsO. — The interaction between magnesium a-naphthyl bromide and arseniotis oxide is represented as taking place as follows ... 

Di-a-naphthylarsenious sulphide, (CioH7)a-A sS, is formed either by the interaction of magnesium a-naphthyl bromide and arsenic trisulphide, or by treating the corresponding oxide or chloride with hydrogen sulphide in the usual way. The sulphide melts at 185° to 186° C. 

When freshly precipitated silver chloride is used instead of the bromide, a brown, granular powder is obtained. When dry it readily decomposes, evolving clouds of diphenyl fumes. The ratio of silver to phenyl appears to be as 1 1. With magnesium p-xylyl- and a-naphthyl bromides and the magnesium compound of p-bromodiphenyl ether, similar compounds are isolated,... 

Thallium di-a-naphthyl bromide, prepared from magnesium a-naphthyl bromide and thallie chloride, is a fawn, crystalline powder, melting at 272° C. and is completely soluble in cold pyridine, insoluble in toluene. 

AS2O3 with the Grignard reagent from 1-naphthyl bromide followed by deeom-position with hydrochlorie aeid. The resolution into optically active isomers of the arsenic(ni) compounds (115) as hydrogen tartrates and the arsonium salts... 

Recently, the use of a chiral catalysts in the asymmetric biaryl synthesis has received some attention. Unsymmetrical chiral binaphthyls can be obtained in high enantiomeric excess by SnAt reactions of naphthylimines such as 39 with lithium bromide free 1-naphthyllithium catalysed by a chiral ether ligand 40 (ref. 29). Another example is the Ni(0) catalysed cross coupling of naphthyl Grignard reagents and naphthyl bromides in the presence of a chiral ferrocene ligand (ref. 30). 

However, in the Suzuki-Miyaura reaction of relatively simple, enantiomerically pure, both naphthyl bromides and naphthylboronic acids gave diastereomeric mixtures, indicating rather low diastereoselectivity [21]. More important access to axially chiral biaryls is the Meyers approach in its diastereoselective version [22-25]. It was foimd that oxazolines, derived from readily available amino alcohol 585 [22], underwent the Meyers synthesis of biaryls giving the expected biaryls in high d.e. s [23-25]. Thus l-methoxynaphthyl-2-carboxamide (586) was activated with triethyloxonium tetrafluoroborate to 587, which reacted with 585 to give the oxazoline 588. The latter... 

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