著者

岩渕 好治 畑山 範

出版者

The Society of Synthetic Organic Chemistry, Japan

雑誌

有機合成化学協会誌 (ISSN:00379980)

巻号頁・発行日

vol.60, no.1, pp.2-14, 2002-01-01 (Released:2009-11-13)

参考文献数

47

被引用文献数

39 57

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The Morita-Baylis-Hillman reaction, α-hydroxyalkylation of activated olefins, has attracted considerable research interest because of the synthetic utility of the densely functionalized product as well as the exquisite tandem Michael-aldol reaction process under nucleophilic catalysis. This review gives an overview on recent remarkable progress in the Morita-Baylis-Hillman reactions. Several other successful methods affording the Morita-Baylis-Hillman type adducts are also reviewed by focusing their imaginative strategies.

著者

高野 誠一 畑山 範 高橋 召 高橋 洋子 岩田 裕光 宍戸 宏造 小笠原 国郎

出版者

天然有機化合物討論会実行委員会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

vol.21, pp.50-57, 1978

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A new synthetic approach to the alkaloids related to emetine (3) and quinine(5) from norbornylene(1) is described. Norbornylene(1) was transformed into (±)-norcamphor(2) which was oxidized to the bicyclic lactone(8) by Baeyer-Villiger oxidation then alkylated with ethyl bromide and allyl bromide in a stereospecific fashion to give (9) and (29), respectively. The former lactone(9) was converted into the emetine precursor(21) and protoemetinol(4) both in dl form via the α-diketone monothioketal (13). The latter lactone(29) was converted into the homomeroquinene equivalent(37) via the α-diketone monothioketal(32) which was then transformed into dl-meroquinene aldehyde(6) via the olefin formation through the phenylselenide(41). Since norbornylene(1) has been converted into a chiral norcamphor(2), the present method would be applicable to the synthesis of the above alkaloids together with various indole alkaloids in a chiral form.

著者

今井 直子 オニヤンゴ エヴァンス 鶴本 穣治 高橋 圭介 石原 淳 畑山 範

出版者

天然有機化合物討論会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

no.48, pp.181-186, 2006-09-15

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Oxazolomycin and neooxazolomycin are structurally closely related antibiotics isolated from Streptomyces sp. by Uemura et al. The former is the parent member of a class of polyene bicyclic antibiotics, other members being oxazolomycin B and C, 16-methyloxazolomycin, and curromycin A and B. The oxazolomycins were found to exhibit wide ranging and potent antibiotic activity, including inhibitory activity against Gram-positive bacteria, antiviral activity against vaccina, herpes simplex type I and influenza A, as well as in vivo antitumor activity. The intriguing molecular architectures and the biological activities make these compounds attractive targets for synthesis. However, the total synthesis is limited to Kende's synthesis of neooxazolomycin. We report here a novel approach to neooxazolomycin, which can be also applicable to the synthesis of oxazolomycin. Our synthesis of right hand core 22 started with methyl (S)-hydroxyisobutyrate and proceeded through three major transformations involving regio- and stereoselective iodination via intramolecular Pt-catalyzed hydrosilylation, Pd-catalyzed enolate alkenylation, and stereoselective dihydroxylation accompanied by concomitant lactonization. Nozaki-Hiyama-Kishi coupling of aldehyde 23 obtained from 22 with N-Fmoc-iododienamine 24 gave 7S-isomer 25 and 7R-isomer 26 as a 1: 1 epimeric mixture. It was gratifyingly found that Dess-Martin oxidation of this epimeric mixture followed by L-Selectride reduction of the resulting ketone produced the desired 7R-isomer 26 in excellent stereoselectivity (94% de). Removal of the silyl protecting group allowed us to obtain the Kende's intermediate 27, the synthesis of which constitutes a formal synthesis of neooxazolomycin.