Yoshikazu Makioka

Yb/TMS-Br promoted homocoupling reactions of aliphatic ketones and α,β-unsaturated ketones

Abstract Ytterbium metal reacts with trimethylsilyl bromide (TMS-Br) to give divalent YbBr 2 . YbBr 2 thus formed in situ, causes coupling reactions of aliphatic ketones and α,β-unsaturated ketones to give bissilylated 1,2-diols and 1,6-ketones, respectively, in good yields.

A facile generation of organosamariumη3-allyl complexes by reductive cleavage of allylic ethers with (C5Me5)2Sm(THF)n

Abstract Reductive C-O bond cleavage of allylic benzyl ethers with two equivalents of (C 5 Me 5 ) 2 Sm(THF) n (n=2 or 0) takes place selectively to generate(C 5 Me 5 ) 2 Sm(η 3 -allyl) complexes in high yields along with equimolar amounts of the samarium benzyloxide.

Generation of allenic samarium complexes from propargylic ethers and (C5Me5)2Sm(thf)2, and their electrophilic trapping

Allenic samarium complexes are readily generated in high yields by the reaction of propargylic benzyl ethers with (C5Me5)2Sm(thf)2. Electrophilic trapping of the complexes derived from the secondary and tertiary ethers with cyclohexanone and dimethylphenylsilyl chloride gives the corresponding propargylic products selectively, whereas α-allenic alcohols are predominantly obtained in the reaction of the complexes, generated from the primary ethers, with cyclohexanone.

Convenient preparation and reaction of a divalent ytterbium thiolate

Abstract Ytterbium metal (Yb) reacts with phenylthiotrimethylsilane to generate ytterbium(II) phenylthiolate. The divalent ytterbium thiolate [Yb(SPh) 2 ], thus formed in situ, reacts with aromatic aldehydes to give pinacols.

Novel deoxygenative acylation of diaryl ketones with acylsilanes mediated by lanthanoid metals

Abstract The reaction of diaryl ketones and benzoyltrimethylsilane is mediated by lanthanoid metals such as ytterbium to give the deoxygenatively acylated product, 1,1-diarylacetophenones in good yields. In the reaction with acetylsilane, the corresponding silyl enol ether was obtained in a moderate yield.