Keiji Tanino

Total synthesis of ingenol, a diterpene isolated from the genus Euphorbia, was accomplished on the basis of the novel key reactions. The highly strained ingenane skeleton was constructed through an intramolecular cyclization reaction of an acetylene dicobalt complex followed by a rearrangement reaction of an epoxy alcohol. The C(3),C(4),C(5)-triol moiety was introduced by a stereoselective double dihydroxylation reaction of a diene having C(2)-C(3) and C(4)-C(5) double bonds.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Novel [5+2] Cycloaddition Reaction Using a Dicobalt Acetylene ComplexKeiji Tanino, Tadashi Shimizu, Motoki Miyama, and Isao KuwajimaView Author Information Division of Chemistry, Graduate School of Science Hokkaido University, Sapporo 060-0810, Japan Department of Chemistry Tokyo Institute of Technology Meguro, Tokyo 152-8551, Japan Laboratory for Natural Products Chemistry Kitasato University, S-105 1-15-1 Kitasato, Sagamihara 228-8555, Japan

[reaction: see text] A [5 + 2] cycloaddition reaction of a new five-carbon unit was developed on the basis of a dicobalt hexacarbonyl propargyl cation species. Under the influence of EtAlCl(2), [5-benzoyloxy-2-(triisopropylsiloxy)-1-penten-3-yne)]dicobalt hexacarbonyl reacted with enol triisopropylsilyl ethers to yield seven-membered dicobalt acetylene complexes in good yield. The reactions with cyclic enol silyl ethers as well as acyclic enol silyl ethers exhibited remarkably high diastereosele

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Novel Method for Inside Selective Silylation of 1,2-DiolsKeiji Tanino, Tadashi Shimizu, Michio Kuwahara, and Isao KuwajimaView Author Information Department of Chemistry, Tokyo Institute of Technology, Meguro, Tokyo 152, Japan Cite this: J. Org. Chem. 1998, 63, 8, 2422–2423Publication Date (Web):March 28, 1998Publication History Received10 December 1997Published online28 March 1998Published inissue 1 April 1998https://pubs.acs.org/doi/10.1021/j

To expand the originally developed fluorescent 1,3a,6a-triazapentalenes as fluorescent labelling reagents, the fluorescence wavelength of the 1,3a,6a-triazapentalenes was extended to the red color region. Based on the noteworthy correlation of the fluorescence wavelength with the inductive effect of the 2-substituent, electron-deficient 2-(2-cyano-4-methoxycarbonylphenyl)-1,3a,6a-triazapentalene and 2-(2,6-dicyano-4-methoxycarbonylphenyl)-1,3a,6a-triazapentalene were synthesized. The former exhi

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTControl of Stereochemistry by σ-Participation of a Silyl Group. A Novel Method for Diastereoselective Polyol SynthesisKeiji Tanino, Naoei Yoshitani, Fumiko Moriyama, and Isao KuwajimaView Author Information Department of Chemistry, Tokyo Institute of Technology, Meguro, Tokyo 152, Japan Cite this: J. Org. Chem. 1997, 62, 13, 4206–4207Publication Date (Web):June 27, 1997Publication History Received25 February 1997Published online27 June 1997Publis