Triethylsilane aryl halides

Vinyl and Aryl Halides and Triflates. The organosilane reduction of aryl halides is possible in high yields with triethylsilane and palladium chloride.195 The reaction is equally successful with aryl chlorides, bromides, and iodides. Aryl bromides and iodides, but not chlorides, are reduced with PMHS/Pd(PPh3)4 in moderate to excellent yields.199 This system also reduces vinyl bromides.199 p-Chlorobenzophenone is reduced to benzophenone with yym-tetramethyldisilo-xane and Ni/C in excellent yield (Eq. 59).200 There is a report of the organosilane reduction of aryl and vinyl triflates in very high yields with the combination of Et3SiH/Pd(OAc)2/dppp (l,3-bis(diphenylphosphino)propane) (Eq. 60).201... 

Aryl halides can be dehalogenated with triethylsilane in the presence of a palladium catalyst. The method is versatile and can also be used for the reduction of acyl chlorides to aldehydes, or benzylicbromides to the corresponding hydrocarbons. If different types of halides are present in the molecule, selective dehalogenation takes place. Thus, an aryl iodide can be reduced in the presence of a chloride, and benzylic bromide is reduced more easily than an aryl bromide. Finally, the method is even able to distinguish between two aryl bromides in the same molecule (Scheme 4.41)67. 

Villemin, D. and Nechab, B., Rapid and efficient palladium catalysed reduction of aryl halides by triethylsilane under microwave irradiation, /. Chem. Res. (S), 2000, 432-434. 

In addition to the silylation of aryl halides, alkenyl iodides can also be silylated in the presence of a palladium(O) catalyst (eq 22). This silylation proceeds stereoselectively with retention of the carbon-carbon bond stereochemistry, with neither the a-nor (Z)-isomer being produced. The byproduct that arises from this reaction is the saturated /3-aryl triethoxysilane resulting from hydrosilylative reduction of the olefin (97 3 unsaturated saturated). Interesting to note is the increased observance of this saturated byproduct in the presence of other silanes, including dimethoxymethylsilane (93 7), triethylsilane (87 13), dimethylphenylsilane (87 13) and triphenylsilane (90 10), once again demonstrating the specific advantage of triethoxysilane. The alkenylsilanes produced in this reaction are versatile intermediates that have been used effectively in other synthetic transformations. ... 

Classical synthetic routes to arylsilanes consist of the reaction of aryl Grignard or aryllithium compounds with silicon electrophiles and many of these routes are presented in the various reviews. Recently, metal-catalyzed reactions of aryl halides with silanes have proven to be useful routes to functionalized arylsilanes. Alami reported the first platinum-catalyzed selective silylation of aryl iodides and bromides 9 having electron-withdrawing group to give arylsilanes 10 with triethylsilane and sodium... 

The reductive dehalogenation of aryl halide by triethylsilane with catalytic amount of palladium chloride under microwave irradiation is a simple, efficient and selective method. The silicon hydrides are nontoxic and stable and hence, these are effective reducing agents. 

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