- Synthesis of 2,2,5,5-Tetrasubstituted 1,4-Dioxa-2,5-disilacyclohexanes via Organotin(IV)-Catalyzed Transesterification of (Acetoxymethyl)alkoxysilanes
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(Acetoxymethyl)silanes 2, 7 a-c, and 10 a-c with at least one alkoxy group, of the general formula (AcOCH2)Si(OR)3-n(CH 3)n (R: Me, Et, iPr; n=0, 1, 2), were synthesized from the corresponding (chloromethyl)silanes 1, 6 a-c, and 9 a-c by treatment with potassium acetate under phase-transfer-catalysis conditions. These compounds were found to provide 2,2,5,5-organo-substituted 1,4-dioxa-2,5- disilacyclohexanes 3, 8 a-c, and 11 a-c if treated with organotin(IV) catalysts such as dioctyltin oxide. The reaction proceeds through transesterification of the acetoxy and alkoxy units followed by ring-closure to form a dimeric six-membered ring. The corresponding alkyl acetates are formed as the reaction by-products. With these mild conditions, the method overcomes the drawbacks of previously reported synthetic routes to furnish 2,2,5,5-tetramethyl-1,4-dioxa-2, 5-disilacyclohexane (3) and even allows the synthesis of 1,4-dioxa-2,5- disilacyclohexanes bearing hydrolytically labile alkoxy substituents at the silicon atom in good yields and high purity. These new materials were fully characterized by NMR spectroscopy, elemental analysis, mass spectrometry, and X-ray analysis (trans-8 a). Tin makes the ring! Easily accessible (acetoxymethyl)silanes with at least one alkoxy group give 2,2,5,5-organo- substituted 1,4-dioxa-2,5-disilacyclohexanes (see figure) in good yields and high purity when treated with organotin(IV) catalysts. The mild reaction conditions even allowed the synthesis of cyclic silanes with hydrolytically labile alkoxy substituents. Copyright
- Erhardt, Sascha A.,Hoffmann, Florian,Daiss, Juergen O.,Stohrer, Juergen,Herdtweck, Eberhardt,Rieger, Bernhard
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- The Reaction of with Triethoxysilane in the Presence of PPh3: a New Method for Synthesis of
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The reaction of with triethoxysilane in the presence of PPh3 is examined under oxygen-free conditions, permitting isolation of 1 formed by elimination of one acac ligand (as protonated and hydrosilylated product) from the nickel complex with its simultaneous silylation which is followed by C-O bond cleavage in triethoxysilyl ligand via a mechanism involving transfer of an ethyl group to Ni with elimination of pentaethoxyhydrodisiloxane in the excess of triethoxysilane.
- Marciniec, Bogdan,Maciejewski, Hieronim,Gulinski, Jacek
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p. 717 - 718
(2007/10/02)
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