Rhenium complex-catalyzed allylation of acetals with allyltrimethylsilane

It was confirmed that the treatment of acetals with allyltrimethylsilane in the presence of a catalytic amount of the rhenium complex, ReBr(CO)₅, gave the corresponding homoallylic ethers in excellent to good yields.     

Domino allylation and cyclization of ortho-alkynylbenzaldehydes with allyltrimethylsilane catalyzed by Pd(II)-Cu(II) bimetallic systems

The reaction of ortho-alkynylated benzaldehydes 1 with allyltrimethylsilane under the Pd(OAc)₂-CuCl₂ catalyst system gave the isochromene derivatives 2 together with the chlorinated products 3. When the reaction was conducted in the presence of half equiv of H₂O, the formation of 3 was suppressed and 2 was obtained in good to high yields. When the reaction of 1a was carried out with trimethylsilylcyanide instead of allylsilane, the cyano group-substituted isochromene 9 was obtained in 94% yield.     

Microwave-assisted allylation of acetals with allyltrimethylsilane in the presence of CuBr

We describe the first synthesis of homoallyl ethers from acetals and allyltrimethylsilane using microwave heating and CuBr as a promoter. This method works best for aromatic acetals, giving the corresponding homoallyl ethers in good to quantitative yield.     

Reaction of allyltrimethylsilane with an aromatic compound using hypervalent organoiodine compound: A new allylation of aromatic compounds

New general method for the allylation of aromatic compounds from allyltrimethylsilane utilizing the combination of iodosylbenzene and BF₃ OEt₂ are described, which is based upon the umpolung of allyltrimethylsilane by way of cationic allylphenyliodonium (III) salt complex as an intermediate.     

Asymmetric allylation of aldehydes and alkylation using "carbon-centered" chiral organosilicon compounds

The effects of the chiral substituents attached to silicon on the stereoselectivity of the reactions of C-centered chiral silicon compounds was examined. The investigation was focused on the asymmetric C-C bond formation reaction of chiral allylsilanes and α-silylallyl anions with aldehydes. The functionalities of the substituents on silicon can be manipulated to improve the stereoselectivities of the reactions remote from silicon atom.     

Synthesis of polyacetylenic montiporic acids by means of organosilicon compounds

A straightforward synthesis of polyacetylenic montiporic acids A and B has been developed, based upon the selective and sequential substitution of the two trimethylsilyl groups of the readily available 1,4-bis(trimethylsilyl)-1,3-butadiyne.     

Bismuth(III) chloride-catalyzed direct deoxygenative allylation of substituted benzylic alcohols with allyltrimethylsilane

A highly effective protocol for allylation of sec-benzyl alcohols with allyltrimethylsilane in the presence of a catalytic amount of bismuth(III) chloride has been developed.     

Synthesis of unsaturated organosilicon compounds from propargyl alcohol

Summary -Trialkylsilylpropargyl and allyl alcohols, and also propargyloxysilanes were synthesized from propargyl alcohol.     

Electrophilic aromatic substitution in triphenylene discotics: Synthesis of alkoxynitrotriphenylenes

Functionalization of triphenylene-based discotic liquid crystals by direct nitration of hexaalkoxytriphenylene has very recently been reported to produce exclusively the mononitrohexaalkoxytriphenylene. W e have found that nitration of such discotics is not restricted to only one ring of triphenylene, but all the three rings can be nitrated successively to produce mononitro-, dinitro- and trinitro-hexaalkoxytriphenylenes. All the mononitro derivatives show a very broad mesophase range. While the dinitrohexabutyloxytriphenylene is non-liquid crystalline, its higher homologues are room temperature liquid crystals. Photomicroscopic pictures of these liquid crystalline materials show classical textures of an ordered hexagonal columnar phase. X-ray diffraction studies of two representative compounds, 4a and 4b, confirmed the above conclusions. None of the trinitro derivatives are liquid crystalline. Nitrotriphenylenes are valuable precursors to several other triphenylene derivatives like amino, acyl, alkylamino, diazo, etc. Mononitration of 2-hydroxy-3,6,7,10,11-pentaalkoxytriphenylenes gives the 1-nitro-2-hydroxy-3,6,7,10,11-pentaalkoxytriphenylenes. These double functionalized triphenylene derivatives are extremely important precursors as the functional group such as nitro, amino, azo, etc. can be utilized to modify the electronic nature of the core and at the same time the hydroxy functional group may be converted to a polymerizable group. Thus, processable oligomers and polymers can be synthesized.