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Stereocontrolled synthesis of carbocyclic compounds with a quaternary carbon atom based on SN2 ' alkylation of γ,δ-epoxy-α,β-unsaturated ketones
Title: | Stereocontrolled synthesis of carbocyclic compounds with a quaternary carbon atom based on SN2 ' alkylation of γ,δ-epoxy-α,β-unsaturated ketones |
Authors: | Yoshimura, Fumihiko Browse this author →KAKEN DB | Kowata, Ayano Browse this author | Tanino, Keiji Browse this author →KAKEN DB |
Issue Date: | 28-Jul-2012 |
Publisher: | Royal Society of Chemistry |
Journal Title: | Organic & Biomolecular Chemistry |
Volume: | 10 |
Issue: | 28 |
Start Page: | 5431 |
End Page: | 5442 |
Publisher DOI: | 10.1039/c2ob25719j |
PMID: | 22706976 |
Abstract: | We developed a new method for stereoselective construction of an all-carbon quaternary stereogenic center on a carbocyclic ring based on regio- and stereoselective SN2' alkylation reactions of γ,δ-epoxy-α,β-unsaturated cyclic ketones. Treatment of the ketones, which were readily prepared in enantiomerically pure form by means of aldol condensations between 3-ethoxy-2-cycloalkenones and α,β-epoxy aldehydes, with a R2Zn-CuCN reagent afforded anti-SN2' products stereoselectively. Conversely, the corresponding syn-SN2' products were stereoselectively obtained through two-step transformations of the same γ,δ-epoxy-α,β-unsaturated cyclic ketones: (1) conversion of the epoxide moiety to a chlorohydrin by treatment with MgCl2 and (2) subsequent SN2' substitution of the chlorohydrin with a R2Zn-CuCN reagent. These substitution products with their chiral trans-allylic alcohol moieties are promising precursors for complex molecules. For example, Eschenmoser-Claisen rearrangement of one of the substitution products resulted in stereoselective formation of a keto amide having contiguous quaternary and tertiary stereogenic centers. |
Rights: | Org. Biomol. Chem., 2012,10, 5431-5442 - Reproduced by permission of The Royal Society of Chemistry (RSC) |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/52793 |
Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 吉村 文彦
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