Enantioselective Total Synthesis of Nitraria Alkaloids: (+)-Nitramine, (+)-Isonitramine, (-)-Isonitramine, and (-)-Sibirine via Asymmetric Phase-Transfer Catalytic α-Allylations of α-Carboxylactams
DC Field | Value | Language |
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dc.contributor.author | Yang, Jewon | - |
dc.contributor.author | Park, Yohan | - |
dc.contributor.author | Yang, Sehun | - |
dc.contributor.author | Lee, Geumwoo | - |
dc.contributor.author | Ha, Min Woo | - |
dc.contributor.author | Kim, Mi-hyun | - |
dc.contributor.author | Hong, Suckchang | - |
dc.contributor.author | Park, Hyeung-geun | - |
dc.date.available | 2021-03-29T00:40:41Z | - |
dc.date.created | 2021-02-09 | - |
dc.date.issued | 2021-03 | - |
dc.identifier.issn | 0022-3263 | - |
dc.identifier.uri | https://scholarworks.bwise.kr/gachon/handle/2020.sw.gachon/80561 | - |
dc.description.abstract | Many optically active 2-azaspirocyclic structures have frequently been found in biologically active natural products. In particular, Nitraria alkaloids, (+)-nitramine, (+)-isonitramine, (-)-isonitramine, and (-)-sibirine, have stereogenicity on their quaternary carbon of the 2-azaspiro[5,5]undecane-7-ol structure. To synthesize Nitraria alkaloids, we developed a new enantioselective synthetic method for chiral α-quaternary lactams via the α-alkylation of α-tert-butoxycarbonyl lactams. α-Alkylation of α-tert-butoxycarboxylactams in the circumstances of phase-transfer catalytic (PTC) system (solid KOH, toluene, and -40 °C) by virtue of the catalytic action of (S,S)-NAS bromide (5 mol %) furnished the corresponding α-alkyl-α-tert-butoxycarbonyl lactams in very high chemical (<99%) and enantioselectivity (<98% ee). Our catalytic methodology was successfully applied for the enantioselective total synthesis of Nitraria alkaloids. (+)-Isonitramine was obtained in 12 steps (98% ee, 43% yield) from δ-valerolactam through enantioselective phase-transfer catalytic allylation, Dieckmann condensation, and diastereoselective reduction as the key reactions. (-)-Sibirine and (+)-nitramine were prepared from (-)-isonitramine or its intermediate. Switching the phase-transfer catalyst from (S,S)-NAS bromide to (R,R)-NAS bromide afforded (-)-isonitramine (98% ee, 41% yield). (-)-Sibirine was synthesized by N-ethoxycarbonylation of (-)-isonitramine followed by reduction (98% ee, 14 steps, 32% yield). Furthermore, the diastereoselective reduction of (R)-2-benzhydryl-2-azaspiro[5.5]undecane-1,7-dione [(R)-15] followed by reductive removal of the diphenylmethyl group successfully gave (+)-nitramine (98% ee, 11 steps, 40% yield). © | - |
dc.language | 영어 | - |
dc.language.iso | en | - |
dc.publisher | American Chemical Society | - |
dc.relation.isPartOf | Journal of Organic Chemistry | - |
dc.title | Enantioselective Total Synthesis of Nitraria Alkaloids: (+)-Nitramine, (+)-Isonitramine, (-)-Isonitramine, and (-)-Sibirine via Asymmetric Phase-Transfer Catalytic α-Allylations of α-Carboxylactams | - |
dc.type | Article | - |
dc.type.rims | ART | - |
dc.description.journalClass | 1 | - |
dc.identifier.wosid | 000631442900001 | - |
dc.identifier.doi | 10.1021/acs.joc.0c02573 | - |
dc.identifier.bibliographicCitation | Journal of Organic Chemistry, v.86, no.6, pp.4375 - 4390 | - |
dc.description.isOpenAccess | N | - |
dc.identifier.scopusid | 2-s2.0-85100177077 | - |
dc.citation.endPage | 4390 | - |
dc.citation.startPage | 4375 | - |
dc.citation.title | Journal of Organic Chemistry | - |
dc.citation.volume | 86 | - |
dc.citation.number | 6 | - |
dc.contributor.affiliatedAuthor | Kim, Mi-hyun | - |
dc.type.docType | Article in Press | - |
dc.description.journalRegisteredClass | scie | - |
dc.description.journalRegisteredClass | scopus | - |
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