Organosilicon gel

Figure 8.5 Synthesis of organosilicon gels, taken from ref. (61) with permission.

Belot V., Corriu R.J.P., Leclercq D., Mutin P.H., Vioux A. Organosilicon gels containing silicon-silicon bonds, precursors to novel silicon oxycarbide compositions. J. Non-Cryst. Solids 1992 144 287-297... 

Scheme 15)62. After terminating the reaction at a conversion of 38% (relative to total amount of substrate rac-78), the product (S)-43 was separated from the nonreacted substrate by column chromatography on silica gel and isolated on a preparative scale in 71% yield (relative to total amount of converted rac-78) with an enantiomeric purity of 95% ee. Recrystallization led to an improvement of the enantiomeric purity by up to >98% ee. The biotransformation product (S)-43 is the antipode of compound (/ )-43 which was obtained by enantioselective microbial reduction of the acylsilane 42 (see Scheme 8)53. The nonreacted substrate (/ )-78 was isolated in 81% yield (relative to total amount of nonconverted rac-78) with an enantiomeric purity of 57% ee. For further enantioselective enzymatic hydrolyses of racemic organosilicon esters, with the carbon atom as the center of chirality, see References 63 and 64. 

In analogy to the organosilicon method for the production of bulk carbides, the formation of ceramic coatings by pyrolysis of organosilane layers on silica gel is studied. As a ceramic precursor, the aminosilane APTS is used. 

Interest in silicon-based materials has established an international conununity whose roots initially dug in organic and silicon chemistry, polymer and sol-gel chemistry, and material science. This fact led Prof. Interrante and Prof. Kawakami to launch a series of workshops that began in Tatsunokuchi, Japan, in 1999 as a satellite workshop to the XU" International Symposium on Organosilicon Chemistry in Sendai. The first workshop was attended by over 100 participants from Asia, Europe, and the USA and its success emphasized the perceived need for a continuing forum for organosilicon polymer research a decision was then taken to maintain these workshops on a bi-annual basis. The second and third workshops were held in Canterbury, UK, in 2001, and Troy, USA, in 2003, both workshops achieved a similarly strong international participation. 

Manuf./Disthb. Acros Org. http //www.acros.be, Alfa Aesar http //www.alfa.com, Dalian Yuanyong Organosilicon http //WWW. organosilicon. com. Gel est http //www.gelest.com, Lancaster Synthesis... 

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