Stepwise Introduction of Different Substituents to α-Chloro-ω-hydrooligosilanes: Convenient Synthesis of Unsymmetrically Substituted Oligosilanes

A series of unsymmetrically substituted oligosilanes were synthesized via stepwise introduction of different substituents to α-chloro-ω-hydrooligosilanes. The reactions of α-chloro-ω-hydrooligosilanes with organolithium or Grignard reagents gave hydrooligosilanes having various alkyl, alkenyl, alkynyl and aryl groups. Thus-obtained hydrooligosilanes were converted into alkoxyoligosilanes by ruthenium-catalyzed dehydrogenative alkoxylation with alcohols.

Hydrocarbon Soluble Recyclable Silylation Reagents and Purification Auxiliaries

Procedures using heptane-phase-selectively soluble octadecyldimethylsilyl groups to facilitate separations and silyl reagent regeneration are described. These results show that alcohols and alkynes protected by these groups are phase-selectively soluble in hydrocarbon solvents. In a thermomorphic cyclohexane/DMF system, >96% of the silylated alcohols are in the cyclohexane phase, allowing these compounds to be purified by a simple liquid/liquid extraction. Applications of these silylating agents in a Grignard synthesis and Sonogashira reaction are described.

A laboratory-scale continuous flow chlorine generator for organic synthesis

A continuous flow chlorine generator for organic synthesis based on the reaction of HCl with NaOCl has been developed.

Carbopalladation of bromoene-alkynylsilanes: mechanistic insights and synthesis of fused-ring bicyclic silanes and phenols

Palladium-catalyzed cyclizations of silylated bromoenynes lead to bicyclic cyclohexadienes that are precursors to enones and phenols. Novel cyclization pathways and mechanistic insights are also disclosed.

Synthesis and reactivity of bis-alkynyl appended metallocenes of Ti, Fe, and Co

(Dimethyl)(phenylethynyl)silyl-substituted cyclopentadiene C5H5SiMe2C2Ph (1) was synthesized by the reaction of in situ generated C5H5SiMe2Cl with LiC2Ph. Metallation of 1 with nBuLi or KN(SiMe3)2 gave the corresponding Li (2) and K (3) salts. Transmetallation of 2 with transition metal halides MCl2 (M = TiCl2, Fe, and Co) generated the corresponding early and late transition metal metallocenes (4, 5, and 6) with pendant alkynyl substituents. Compounds 4 and 6 are the first examples of bis alkyne appended Ti and Co metallocenes. Complexes 5 and 6 undergo alkyne dimerization in the presence of CpCo(CO)2 generating metallocenophanes 7 and 8 incorporating two metal atoms. Compounds 3, 4Cl2, 6, and [8][OTf] have been characterized by single crystal X-ray structure analysis.