- Development of modified Pauson-Khand reactions with ethylene and utilisation in the total synthesis of (+)-taylorione
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Two complementary Pauson-Khanol annulation protocols for use with the gaseous alkene, ethylene, are described. These N-oxide promoted reactions (10 examples) are shown to proceed under both mild autoclave condition or, more conveniently, at atmospheric pressure. The developed methodology has been utilised as the key transformation in the total synthesis of the sesquiterpene (+)-taylorione which has been realised in a good overall yield from readily available (+)-2-carene.
- Donkervoort, Johannes G.,Gordon, Alison R.,Johnstone, Craig,Kerr, William J.,Lange, Udo
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p. 7391 - 7420
(2007/10/03)
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- Reactions of 2-phenylthio-2-cycloalkenones and 2-[phenyl(thiomethyl)]-2-cycloalkenones. Synthesis of some useful chiral and achiral intermediates
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The allyl acetates derived from 2-phenylthio-2-cyclopentenone, 2-phenylthio-2-cyclohexenone, 2-[phenylthio(methyl)]-2-cyclopentenone and 2-[phenylthio(methyl)]-2-cyclohexenone have been hydrolysed by pig liver acetone powder to obtain the corresponding al
- Vankar,Kumaravel,Bhattacharya,Vankar,Kaur
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p. 4829 - 4840
(2007/10/02)
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- An Efficient and Convenient Synthesis of Bridged δ-Lactones
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endo-4-Ethoxycarbonyl-4-(phenylthio)-9-methylene-2-oxabicyclononan-3-ones (5a-c) and their related compounds 5e-h, and endo-4-ethoxycarbonyl-4-(phenylthio)-8-methylene-2-oxabicyclooctan-3-one (5d) were synthesized from α-diazomalonates 3 of 2-(phenylthio)cyclohex-2-en-1-ols (1a-c) and their related compounds 1e-h, and 2-(phenylthio)cyclopent-2-en-1-ol (1d), respectively, via the sigmatropic rearrangement of cyclic allylsulfonium ylides 4.
- Kido, Fusao,Kawada, Yasuhiko,Kato, Michiharu,Yoshikoshi, Akira
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p. 6159 - 6162
(2007/10/02)
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- Regioselective replacement of nitro or sulfonyl group in cyclic α-(nitroalkyl)- or α-(phenylsulfonylalkyl)enones by nucleophiles
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Cyclic α-(nitroalkyl)enones and α-(phenylsulfonylalkyl)enones undergo regioselective substitution of the nitro group by relatively soft sulfur, nitrogen and carbon nucleophiles.
- Tamura, Rui,Katayama, Hitoshi,Watabe, Ken-Ichiro,Suzuki, Hitomi
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p. 7557 - 7568
(2007/10/19)
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- NEW SUBSTITUTION REACTION OF ALLYLIC NITRO COMPOUNDS. REGIOSELECTIVE REPLACEMENT OF NITRO GROUP IN CYCLIC α-(NITROALKYL)ENONES BY NUCLEOPHILES
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Regioselective replacement of nitro group in cyclic α-(nitroalkyl)-enones by various nucleophiles such as stabilized carbanions, amine, NaN3, PhSO2Na and PhSNa provides the overall SN2 type products.
- Tamura, Rui,Tamai, Shinobu,Suzuki, Hitomi
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p. 2413 - 2416
(2007/10/02)
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- -Sigmatropic Rearrangement of an in Situ Prepared Ylide and a Thioether to Thio Ester Conversion as Key Steps in Short Syntheses of Sarkomycin and Its Phenylthio Ester
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2-cyclopent-2-en-1-one (2), which is readily available by the reaction of 2-cyclopentenone with thiophenol, formaldehyde, and triethylamine, is transformed, in high yield and moderate conversion by treatment with (trimethylsilyl)methyl triflate, cesium fluoride, and benzaldehyde, to 2-methylene-3-cyclopentanone (3), which, by the use of trichloroisocyanuric acid (Chloreal), can be quantitatively dichlorinated on the sulfur-bearing carbon atom to 3--2-methylenecyclopentanone (4).This dichloro thioether could be hydrolyzed in good yield to a mixture of sarkomycin phenyl thio ester (5) and sarkomycin (6), containing mainly the former; an additional small amount of sarkomycin can be obtained by hydrolysis of the thio ester in the presence of silver trifluoroacetate and benzhydrol.This procedure represents one of the shortest extant syntheses of sarkomycin and a sarkomycin ester.Model studies of the dichlorination of n-octyl phenyl sulfide (8) to 1-(phenylthio)-1,1-dichlorooctane (9) and various transformations of the latter are also reported.
- Cohen, Theodore,Kosarych, Zenyk,Suzuki, Kunio,Yu, Lin-Chen
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p. 2965 - 2968
(2007/10/02)
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