- Realization of anti-SN2′ selective allylation of 4-cyclopentene-1,3-diol monoester with aryl- and alkenyl-zinc reagents
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(Chemical Equation Presented) Anti-SN2′ mode of allylation of the monoester of 4-cyclopentene-1,3-diol with aryl and alkenyl anions was achieved, for the first time, with the MeOCH2CO2- group as a leaving group to which R-ZnBr and CuCl (as a catalyst) were best fitted. The aryl groups successfully installed were Ph, o- and p-MeC6H 4, o-MOMOC6H4, o-MeOC6H4, and p-F-C6H4, while cis and trans alkenyl groups were attached with retention of the olefinic stereochemistries.
- Nakata, Kenya,Kiyotsuka, Yohei,Kitazume, Tomoya,Kobayashi, Yuichi
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experimental part
p. 1345 - 1348
(2009/05/07)
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- New reagent system for attaining high regio- and stereoselectivities in allylic displacement of 4-cyclopentene-1,3-diol monoacetate with aryl- and alkenylmagnesium bromides
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(Chemical Equation Presented) Low regioselectivity of RMgBr (R = aryl, alkenyl) in the CuCN-catalyzed reaction with 4-cyclopentene-1,3-diol monoacetate is improved by addition of LiCl or MgCl2 to a similar extent as previously obtained with RMg
- Kobayashi, Yuichi,Nakata, Kenya,Ainai, Takayuki
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p. 183 - 186
(2007/10/03)
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- Palladium-catalyzed reaction of 4-cyclopentene-1,3-diol monoacetate with Grignard reagents producing hitherto unreachable cis-1,2-isomers
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Reaction of 4-cyclopentene-1,3-diol monoacetate with RMgCl (R = alkyl, aryl) in the presence of a palladium catalyst proceeded with retention of configuration to give cis-1,2-regio-isomers as the major products.
- Hattori, Hatsuhiko,Abbas, Ashraf A.,Kobayashi, Yuichi
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p. 884 - 885
(2007/10/03)
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- A new reagent system for installation of an aryl group onto the monoacetate of 4-cyclopentene-1,3-diol
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Among the three types of reagents from PhMgX (X=Br, Cl) and CuCN for phenylation of 4-cyclopentene-1,3-diol monoacetate, PhMgCl/CuCN (cat.) and Ph2Cu(CN)(MgCl)2 in THF afforded the trans-1,4-isomer efficiently (82-87% yields, 91-93% regioselectivity). Similarly, o- and p-RC6H4MgCl (R=Me, OMe, CH2=CH) in combination with CuCN furnished good to excellent reactivity and regioselectivity. As an application, a three-step synthesis of dihydromultifidene was accomplished successfully.
- Ainai, Takayuki,Ito, Michiko,Kobayashi, Yuichi
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p. 3983 - 3986
(2007/10/03)
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