deep purple (the color of Fp2). We could not detect any other organic products.Preparation of Enolate Complexes 6c,d and 8c,d. 1,3-Dioxolanes (acetals) of -halo ketones were prepared by the published method.32 NaFp or Na/KFp* (10 mmol) in THF (10 mL) was added to a THF solution (20 mL) of appropriate 1,3dioxolane (12 mmol) at -78 °C. After the mixture was stirred for 3 h at room temperature, the volatiles were removed under reduced pressure. The product was extracted with ether (100 mL) and filtered through silica gel. The acetal linkage was hydrolyzed by stirring with 1/10 N HCl(aq), and then the organic layer was dried over MgS04. 6 and 8 were isolated by column chromatography followed by recrystallization from Et^O. 6c: 50% yield. 6d: 48% yield; yellow prisms; mp 90 °C. Anal. Caled for

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Hauptbestandteile des insgesamt 34 Komponenten umfassenden Produktgemisches sind Formaldehyd, Methan, Methoxyacetaldehyd, Äthylenglykol, Äthanol, Methanol und Wasserstoff.

ChemInform Abstract The photolysis of the acylsilanes (III) gives silenes (IV), whose subsequent chemistry is dependent on the steric size of the substituents R1 and R2 and on their facile photochemical excitation by UV light. Thus, from (IVa) a head-to-head dimerization occurs to form the 1,2-disilacyclobutane (V). (IVb) is a stable silene, which on subsequent photolysis isomerizes to a new silene (VI), which in turn produces the head-to-tail dimerization products (VII) and (VIII). Depending on the substituent R2 the two routes of photolysis occur in the case of (IIIc). The results show that each acylsilane on photolysis forms only one of the two possible silene geometric isomers, which react nonstereospecifically when trapped by added methanol. The stereochemistry of the reactions and the mechanism of the silene-to-silene rearrangements is discussed.