Silicon compounds arylation

Aryl-S02Cl. At present only a few data concerning electrophilic 1,3-substitution with allenic and acetylenic tin or silicon compounds are available. 

Acetyl hypofluorite is very effective m the fluorination of the aryl-metal (Hg, Ge, or Si) bond, but yields are frequently low. With aryl silicon compounds some competition exists for replacement of an aromatic hydrogen [5i, 52, 55, 54] (equations 25-27). Fluoroxytrifluoromethane fluorinates p-methoxypheny 1 mercuric acetate to givep-fluoroanisole in 86% yield [52]... 

The reaction described is of considerable general utility for the preparation of benzoyloxy derivatives of unsaturated hydrocarbons.2"8 Reactions of 2-butyl perbenzoate with various other classes of compounds in the presence of catalytic amounts of copper ions produce benzoyloxy derivatives. Thus this reaction can also be used to effect one-step oxidation of saturated hydrocarbons,9, 10 esters,6,11 dialkyl and aryl alkyl ethers,12 14 benzylic ethers,11,15 cyclic ethers,13,16 straight-chain and benzylic sulfides,12, 17-19 cyclic sulfides,11,19 amides,11 and certain organo-silicon compounds.20... 

Aryloxytitanium halides, 25 83 2-Arylpyridines, 27 111 Aryl phosphate esters, 79 51 Aryl phosphates, 7 7 493 Aryl phosphonates, 79 37 Arylphosphorus compounds, 79 28 Aryls, palladium, 79 652 Aryl-silicon compounds, 22 553, 554 Arylsulfinic acids, 27 248-249 Arylsulfonylated gelatin, 72 444 Aryltin trihalides, 24 810-811 Arylyl amines, 70 396-399 Asahi Chemical Industries EHD processes, 9 676-677 sebacic acid production, 9 679-680 ASAM (alkaline-sulfite-AQ-methanol) process, 27 30... 

Ethers of orthosilicon acid and their derivatives, tetraalkoxy(aroxy)silanes and alkyl(aryl)alkoxy(aroxy)silanes are a rather extensive class of silicone compounds. They are independently applied in various spheres of technology, but are particularly valuable as semi-products for preparing important silicone oligomers and polymers. 

Perfluoroalkyl and -aryl bromides can be used in association with certain phosphorus compounds. as with silicon compounds, to introduce the fluorinated group as an anionic spe-... 

Aryl silicon compounds can be prepared by metal-catalysed reaction of halides with silanes, as in the rhodium-catalysed reaction below. The mechanistic details of this reaction (probably) differ from the palladium-catalysed borane reaction. (NOTE triethoxy silane is extremely toxic )... 

Biphenyls. Aryl halides can couple with aryltin and silicon compounds... 

B.iv.d. Cross-Coupling Reactions Involving Silicon Compounds. A very recent example is reported for the cross-coupling of aryl(fluoro)silanes with aryl iodides attached to solid support. 

Silicon compounds containing reactive aryl groups may be chlorosulfonated without loss of the silicon atom by the use of chlorosulfonic acid. Thus, tetraphenoxysilane 451 reacted with excess chlorosulfonic acid at 75-85 C (2j hours) to give the sulfonyl chloride 452. Subsequent reduction of 452 with zinc afforded 4-hydroxyphenylthiol 453 (72% yield, 99.6% purity) this provides an excellent synthetic route to this compound (Equation 140). ... 

Isomeric mixtures of chlorotetrafluorophenyl-silicon compounds and thence bis-silicon derivatives have been prepared by Grignard routes based upon dichlorotetrafluorohenzene (80% l,3-C,CljF4) (see Scheme 27). > A variety of mono-, bis-, and tris-trimethylsilyl-derivatives have been prepared from 1,3-dichloroletrafluoro- and 1,3,5-trichIorotrifluoro-benzene using routes based on aryl-lithium compounds (see Scheme 28). ... 

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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