- Organosubstitutierte 1,6-Dioxa-2-sila-5-bora-3-cycloalkene - Herstellung und Charakterisierung
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Organosubstituted 1,6-Dioxa-2-sila-5-bora-3-cycloalkenes - Preparation and Characterisation The cis alkenes ROSi(CH3)2C(R)=C(C2H5)B(C2H5)OR (R=CH3: 11; C2H5: 12; C6H5: 13) are prepared from CH3NSi(CH3)2C(R)=C(C2H5)BC2H5 A; R=C(CH3)=CH2: B> with the monohydroxy compounds ROH (R= CH3, C2H5, C6H5).A or B react with aliphatic dihydroxy compounds HO-R'-OH to give 8-,9-, and 10-membered ring compounds OSi(CH3)2C(R)=C(C2H5)OR'.A is initially cleaved at the SiN bond with formation of 14.Compound 15a crystallises as the 16-membered (15a)2 (X-ray structure analysis).The aromatic dihydroxy compounds catechol (7), resorcinol (8), 2,3-dihydroxynaphthalene (9), 1,8-dihydroxynaphthalene (10) react with A to form 21 to 24, but mainly by protolytic BCvinyl fission to give the 2,5-dihydro-1,2,3-dioxaboroles (e.g. 7f1, 9f1, 10f1) and the acyclic boron-free compounds 7f3, 9f3, 10f3 or the dyotropic rearranged isomers 7f3', 9f3', 10f3'.The MS and NMR (1H, 11B, 13C, 29Si) data of the new compounds are discussed.
- Koester, Roland,Seidel, Guenter,Boese, Roland,Wrackmeyer, Bernd
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p. 1013 - 1028
(2007/10/02)
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- Process for the separation and purification of oligo and polyhydroxy compounds and borate esters thereof
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A process for the separation and/or purification of oligo- and polyhydroxy compounds by introducing and subsequently eliminating protective groups, wherein oligo- and polyhydroxy compounds are reacted with bis(ethyl-pivaloyloxy)-diboroxane or ethylboroxine, optionally in inert solvents, the resulting O-ethylboranodiyl derivatives of the hydroxy compounds are separated off and the O-ethylboranodiyl protective groups are eliminated by alcoholic compounds, for example methanol or glycol.
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