Masayuki Inoue

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConvergent Strategies for Syntheses of trans-Fused Polycyclic EthersMasayuki InoueView Author Information Department of Chemistry and Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan Cite this: Chem. Rev. 2005, 105, 12, 4379–4405Publication Date (Web):October 22, 2005Publication History Received1 March 2005Published online22 October 2005Published inissue 1 December 2005https://pub

Direct substitution of hydrogen in C(sp3)–H bonds by 4-pyridine was achieved by employing benzophenone and 4-cyanopyridine in aqueous acetonitrile under photo-irradiating conditions. This simple and mild 4-pyridination proceeds in a highly chemoselective manner especially at benzylic C(sp3)–H bonds without affecting polar functional groups, and enables intermolecular formation of sterically hindered bonds between alkylaromatics and 4-pyridine. The present methodology thus serves as a powerful to

More than 20,000 people suffer annually from ciguatera seafood poisoning in subtropical and tropical regions. The extremely low content of the causative neurotoxins, designated as ciguatoxins, in fish has hampered isolation, detailed biological studies, and preparation of anti-ciguatoxin antibodies for detecting these toxins. Furthermore, the large (3 nm in length) and complex molecular structure of ciguatoxins has impeded chemists from completing their total synthesis. In this article, the full

Two concise syntheses of (+/-)-frondosin B (1), an interleukin-8 receptor antagonist, have been achieved from commercially available 5-methoxysalicylaldehyde. The seven-membered ring in ketone 33, the common intermediate for both syntheses, was built by a classical Friedel-Crafts reaction. The key step of the first route was facile cationic cyclization of the vinylogous benzofuran to the trisubstituted olefin (30 --> 16 + 38) to construct a six-membered carbocycle. Although this route demonstrat

The direct alkenylation of C(sp3)–H bonds was achieved by employing benzophenone and 1,2-bis(phenylsulfonyl)ethylene under photo-irradiation conditions. This simple metal-free reaction enables the substitution of heteroatom-substituted methine, methylene and aliphatic C(sp3)–H bonds by (E)-sulfonylalkene units in a highly chemoselective manner. The derived sulfonylalkenes were further converted in a single step to the prenyl derivatives via a second photo-induced radical substitution and to the

[structure: see text] Ciguatoxin CTX3C is a representative congener of ciguatoxins, which are known to be the principal causative agents of ciguatera seafood poisoning. The structure of CTX3C spans more than 3 nm and is characterized by 13 ether rings. In this paper, an improved total synthesis of CTX3C is reported. Alteration of the protective group from benzyl ether to 2-naphthylmethyl (NAP) ether drastically increases the yield for final global deprotection and has provided a sufficient amoun

Macrocyclic natural products have been recognized and utilized as new platforms for designing drugs in pharmaceutical research because the constrained three-dimensional shapes and the large surface areas of these complex structures enable selective binding to conventionally undruggable targets. Since natural products are not necessarily ideal for medicinal use, structural optimization is required to obtain superior drug candidates. However, the modifications to macrocyclic natural products that

Merrilactone A (1) has been shown to possess neurotrophic activity and thus is expected to hold therapeutic potential in the treatment of neurodegeneration diseases. In this paper, we report the total synthesis of (+/-)-1, employing, as key steps, a novel desymmetrization protocol of meso-diketone to construct the core cis-bicyclo[3.3.0]octyl system of 1 (3 --> 2) and a radical cyclization to install the highly congested C9-quaternary carbon (16 --> 17).

Ciguatoxins, the principal causative toxins of ciguatera seafood poisoning, are large ladder-like polycyclic ethers with the 13 ether rings ranging from five- to nine-membered. In this paper, we describe the total synthesis of the two most toxic members of the ciguatoxin family, ciguatoxin 1 and 51-hydroxyCTX3C 2, based on a unified synthetic strategy. The key features in our syntheses were (i) direct construction of the O,S-acetal from the corresponding left and right wing fragments (3, 4, 14);

A general strategy for photochemical alkynylation of unreactive C(sp(3))-H bonds has been developed. After C-H abstraction by the photo-excited benzophenone, a two-carbon unit was efficiently transferred to the generated radical from 1-tosyl-2-(trimethylsilyl)acetylene to afford the alkynylated product. The present reaction enables construction of various tri- and tetra-substituted carbons from heteroatom-substituted methylenes, methines and alkanes in a highly chemoselective fashion, and would

The complex ABC-tricyclic structure of crotophorbolone, a derivative of the tigliane diterpenoids, was assembled by coupling of simple fragments. The six-membered C-ring fragment, having five contiguous stereocenters, was stereoselectively constructed from (R)-carvone. After attachment of the five-membered A-ring through the π-allyl Stille coupling reaction, the α-alkoxy bridgehead radical reaction effected the endo-cyclization of the seven-membered B-ring by forming the sterically congested bon