Trimethylstannyl-naphthalene

The bromo derivative of A -mcthylsuccinimide did also undergo Suzuki coupling when treated with naphthylboronic acid in the presence of palladium acetate, triphenylphosphine and potassium carbonate (6.3.). The coupled product was deprotected under the reaction conditions and an indole derivative was isolated in good yield, which was successfully converted into the hexacyclic naphthopyrrolo[3,4-c]carbazole structure. Using the analogous trimethylstannyl-naphthalene derivative and optimised Stille coupling conditions the desired product was isolated only in 56% yield.5... 

There has been an incomplete report of the ESR spectrum of PhSnMe with a(2H-ortho) 0.40 mT and aQi-para) 0.82 mT, suggesting that the /s MO is stabilised and that the Me3Sn substituent is electron-attracting.89 The spectrum of the radical anion of l,4-bis(trimethylstannyl)naphthalene (20-18) has also been obtained by treating the substrate with potassium in DME,90 but this is not so informative as naphthalene is not orbitally degenerate, and the spin distribution is not so sensitive to substituent effects. 

Silicon Substitutions.— The double Friedel-Crafts reaction of chloro-methyltrichlorosilane (ClCH2SiCl3) with benzene and AICI3 yields 75% of mainly p-(with some o- and m-)di(trichlorosilylmethyl)benzene, previously unknown. Trimethylsilylbenzenes can be prepared directly by reaction between aryl chlorides, bromides, or iodides, hexamethyldisilane, and KOMe (or the Na or Li salts) in HMPT at 25 °C for 3 h. Yields are in the range 63-92%, depending on the nature of the aryl halide the major side-product is ArH. The mechanism is not known, but may involve an Ar-K intermediate. l,8-Bis-(trimethylsilyl)- and -(trimethylstannyl)-naphthalenes have been prepared from the 1,8-dilithio-compound and McaSiCl or MesSnCl. The n.m.r. spectra seem to imply that there is much greater hindrance to rotation about the C—Si than about the C—Sn bonds thus the silicon compound displays three methyl resonances (incredibly)... 

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