Itaru Nakamura

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTransition-Metal-Catalyzed Reactions in Heterocyclic SynthesisItaru Nakamura and Yoshinori YamamotoView Author Information Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan Cite this: Chem. Rev. 2004, 104, 5, 2127–2198Publication Date (Web):February 21, 2004Publication History Received12 August 2003Published online21 February 2004Published inissue 1 May 2004https://pubs.acs.org/doi/10.1021/cr020095ihttps://d

The transition metal-catalyzed formal [3+2] cycloaddition of methylenecyclopropanes with unsaturated compounds X=Y, such as alkenes, aldehydes, and imines, gives five-membered carbocycles or heterocycles. The Heck-type reaction of R-Pd-X with the exomethylene part of methylenecyclopropanes gives the corresponding cyclopropylcarbinylpalladium complexes which undergo further transformations through typical palladium reactions such as β-hydride elimination or reductive elimination of Pd(0). Hydrost

Gold forms rings: AuCl-catalyzed cyclization of (α-alkoxy alkyl) (ortho-alkynyl phenyl) sulfides 1 proceeds under mild conditions to give 3-(α-alkoxy alkyl) benzothiophenes 2 in high yields for a wide range of substrates (see scheme). The starting materials are readily available through acetalization of ortho-bromobenzenethiol and subsequent Sonogashira coupling. This methodology provides an atom-economic route to sulfur-containing heteroarenes. Supporting information for this article is availab

Goldene Zeiten für schweflige Ringe: Eine AuCl-katalysierte Cyclisierung verschiedener (ortho-Alkinylphenyl)-(α-alkoxyalkyl)sulfide 1 ergab unter milden Bedingungen die 3-(α-Alkoxyalkyl)benzothiophene 2 in hohen Ausbeuten. Die Ausgangsverbindungen erhält man leicht durch Acetalisierung von ortho-Brombenzolthiol und anschließende Sonogashira-Kupplung. Dieses Verfahren öffnet eine atomökonomische Route zu Schwefelheteroarenen. Supporting information for this article is available on the WWW under h

The PtCl2-catalyzed cyclization reaction of o-alkynylphenyl acetals 1 in the presence of 1,5-cyclooctadiene produces 3-(alpha-alkoxyalkyl)benzofurans 2 in good to high yields. For example, the reaction of acetaldehyde ethyl 2-(1-octynyl)phenyl acetal (1a), acetaldehyde ethyl 2-(cyclohexylethynyl)phenyl acetal (1c), and acetaldehyde ethyl 2-(phenylethynyl)phenyl acetal (1f) in the presence of 2 mol % of platinum(II) chloride and 8 mol % of 1,5-cyclooctadiene in toluene at 30 degrees C gave the co

Consecutive formation of CN and CS bonds: The gold-catalyzed intramolecular aminosulfonylation of 2-alkynyl-N-sulfonylanilines 1 (R1=H) produces 3-sulfonylindoles 2 in good to high yields, whereas the indium-catalyzed aminosulfonylation of 2-alkynyl-6-methoxy-N-sulfonylanilines 1 (R1=MeO) affords 6-sulfonylindoles 3 as the major products (see scheme). Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z604038_s.pdf or from the au

The gold-catalyzed cyclization of (ortho-alkynylphenylthio)silanes 1 produced the corresponding 3-silylbenzo[b]thiophenes 2 in good to excellent yields. For example, the reaction of [2-(1-pentynyl)phenylthio]triisopropylsilane 1a, [2-(p-anisylethynyl)phenylthio]triisopropylsilane 1e, and [2-(phenylethynyl)phenylthio]triisopropylsilane 1g in the presence of 2 mol % of AuCl in toluene at 45 degrees C gave 2a, 2e, and 2g in 98, 99, and 97% yields, respectively. This reaction proceeds through intram

Cu-catalyzed cyclizations of (E)-O-propargylic oximes of α,β-unsaturated aldehydes were successfully carried out to afford the corresponding pyridine oxides in good to high yields. As an example, (E)-acrylaldehyde O-1,3-diphenylprop-2-ynyl oxime (1b) was reacted for 5 h in the presence of CuBr(PPh3)3 (10 mol %) and PPh3 (10 mol %) in DMSO at 120 °C to afford 3-benzyl-2-phenylpyridine-N-oxide (2b) in 84% yield. In this case, the reaction proceeded via Cu-catalyzed propargyl oxime-allenyl nitrone

Chirality transfer in gold-catalyzed carbothiolation of o-alkynylphenyl 1-arylethyl sulfides 1 proceeded with retention of the configuration at the 1-arylethyl group. This result suggests that the [1,3] migration of 1-arylethyl group proceeds through formation of the contact ion pair B followed by C-C bond formation.

Multiply substituted tetrahydrofuran rings can be prepared by the [3+2] cycloaddition of alkylidenecyclopropanes 1 with aldehydes 2 [Eq. (1)]. In this reaction, the distal bond of the cyclopropane ring is cleaved, and 3-methylenetetrahydrofuran derivatives 3 are produced in good yields.

The palladium-catalyzed denitrogenative indolization of N-aroylbenzotriazoles 1 and internal alkynes 2 produced the corresponding polysubstituted indoles 3 in good to high yields. For example, the reaction of 5,6-dimethyl-1-[4-(trifluoromethyl)benzoyl]benzotriazole (1j) with 6-dodecyne (2a), 4-octyne (2b), and diphenylacetylene (2f) in the presence of 10 mol % of Pd(PPh(3))(4) without solvent at 130 degrees C gave the corresponding indoles 3i, 3l, and 3p in 74, 71, and 41% yields, respectively.

A general protocol for the synthesis of functionalized indenes from o-alkynylbenzaldehyde acetals and thioacetals has been elaborated. Acetals uniformly give cyclization products having the alkyl group from the starting acetylene migrated to the alpha-position, whereas the cyclization of the corresponding thioacetals proceeds without alkyl migration. Optimization of the catalytic system for the cyclization of o-alkynylbenzaldehyde acetals revealed an unknown activation effect: PtCl(2) was found

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTRing Opening in the Hydroamination of Methylenecyclopropanes Catalyzed by PalladiumItaru Nakamura, Hitoshi Itagaki, and Yoshinori YamamotoView Author Information Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan Cite this: J. Org. Chem. 1998, 63, 19, 6458–6459Publication Date (Web):September 1, 1998Publication History Received27 July 1998Published online1 September 1998Published inissue 1 September 199

Easy to N-cycle: The efficient synthesis of azepine derivatives was achieved by Rh-catalyzed tandem 2,3-rearrangement involving the heterocyclization of N-allenylnitrone intermediates (see scheme; cod=1,5-cyclooctadiene, tppms=sodium diphenylphosphinobenzene-3-sulfonate). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: T