{"@context":{"@vocab":"https://cir.nii.ac.jp/schema/1.0/","rdfs":"http://www.w3.org/2000/01/rdf-schema#","dc":"http://purl.org/dc/elements/1.1/","dcterms":"http://purl.org/dc/terms/","foaf":"http://xmlns.com/foaf/0.1/","prism":"http://prismstandard.org/namespaces/basic/2.0/","cinii":"http://ci.nii.ac.jp/ns/1.0/","datacite":"https://schema.datacite.org/meta/kernel-4/","ndl":"http://ndl.go.jp/dcndl/terms/","jpcoar":"https://github.com/JPCOAR/schema/blob/master/2.0/"},"@id":"https://cir.nii.ac.jp/crid/1363670318985848320.json","@type":"Article","productIdentifier":[{"identifier":{"@type":"DOI","@value":"10.1002/ejoc.201600766"}},{"identifier":{"@type":"URI","@value":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fejoc.201600766"}},{"identifier":{"@type":"URI","@value":"https://chemistry-europe.onlinelibrary.wiley.com/doi/pdf/10.1002/ejoc.201600766"}}],"dc:title":[{"@value":"Asymmetric Total Synthesis of (–)‐Azaspirene by Utilizing Ti‐Claisen Condensation and Ti‐Direct Aldol Reaction"}],"description":[{"type":"abstract","notation":[{"@value":"<jats:p>A successful asymmetric total synthesis of (–)‐azaspirene has been accomplished by utilizing (3<jats:italic>R</jats:italic>)‐6‐cinnamyl‐3‐methyl‐3‐phenyl‐1,4‐dioxane‐2,5‐dione, a readily accessible chiral template. The present method involves two distinctive TiCl<jats:sub>4</jats:sub>/amine‐mediated reactions: (i) an asymmetric Ti‐crossed‐Claisen condensation of the chiral template with propanoyl chloride followed by methanolysis to afford methyl (2<jats:italic>R</jats:italic>)‐(4<jats:italic>E</jats:italic>)‐2‐hydroxy‐5‐phenyl‐2‐propanoylpent‐4‐enoate, the key chiral synthon and (ii) a robust Ti‐direct aldol addition reaction, instead of the reported lithium diisopropylamide/hexamethylphosphorictriamide (LDA/HMPA) or potassium hexamethyldisilazide (KHMDS)‐mediated reaction, by using the trimethylsilyl (TMS) ether of α‐acyl‐γ‐lactam to successfully furnish the new aldol adduct. Final oxidation, cyclization, and <jats:italic>tert</jats:italic>‐butyldimethylsilyl (TBS) removal produced (–)‐azaspirene from the key template in 23 steps (total yield 1.7 %).</jats:p>"}]}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1383670318985848322","@type":"Researcher","foaf:name":[{"@value":"Mikiko Sugi"}],"jpcoar:affiliationName":[{"@value":"Department of Chemistry School of Science and Technology Kwansei Gakuin University 2‐1 Gakuen 669‐1337 Sanda Hyogo Japan"}]},{"@id":"https://cir.nii.ac.jp/crid/1383670318985848321","@type":"Researcher","foaf:name":[{"@value":"Ryohei Nagase"}],"jpcoar:affiliationName":[{"@value":"Department of Chemistry School of Science and Technology Kwansei Gakuin University 2‐1 Gakuen 669‐1337 Sanda Hyogo Japan"}]},{"@id":"https://cir.nii.ac.jp/crid/1383670318985848324","@type":"Researcher","foaf:name":[{"@value":"Tomonori Misaki"}],"jpcoar:affiliationName":[{"@value":"Graduate School of Material Science University of Hyogo 3‐2‐1 Kohto 678‐1297 Kamigori Hyogo Japan"}]},{"@id":"https://cir.nii.ac.jp/crid/1383670318985848323","@type":"Researcher","foaf:name":[{"@value":"Hidefumi Nakatsuji"}],"jpcoar:affiliationName":[{"@value":"Department of Chemistry School of Science and Technology Kwansei Gakuin University 2‐1 Gakuen 669‐1337 Sanda Hyogo Japan"}]},{"@id":"https://cir.nii.ac.jp/crid/1383670318985848320","@type":"Researcher","foaf:name":[{"@value":"Yoo Tanabe"}],"jpcoar:affiliationName":[{"@value":"Department of Chemistry School of Science and Technology Kwansei Gakuin University 2‐1 Gakuen 669‐1337 Sanda Hyogo Japan"}]}],"publication":{"publicationIdentifier":[{"@type":"PISSN","@value":"1434193X"},{"@type":"EISSN","@value":"10990690"}],"prism:publicationName":[{"@value":"European Journal of Organic Chemistry"}],"dc:publisher":[{"@value":"Wiley"}],"prism:publicationDate":"2016-10","prism:volume":"2016","prism:number":"28","prism:startingPage":"4834","prism:endingPage":"4841"},"reviewed":"false","dc:rights":["http://onlinelibrary.wiley.com/termsAndConditions#vor"],"url":[{"@id":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fejoc.201600766"},{"@id":"https://chemistry-europe.onlinelibrary.wiley.com/doi/pdf/10.1002/ejoc.201600766"}],"createdAt":"2016-08-26","modifiedAt":"2025-10-15","relatedProduct":[{"@id":"https://cir.nii.ac.jp/crid/1360009142908956672","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Highly Oxidized γ-Lactam-Containing Natural Products: Total Synthesis and Biological Evaluation"}]},{"@id":"https://cir.nii.ac.jp/crid/1360567183084828928","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Elucidation of Racemization Process of Azaspirene Skeleton in Neutral Aqueous Media"}]},{"@id":"https://cir.nii.ac.jp/crid/1360848654813239680","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Dehydration‐type Ti‐Claisen Condensation (Carbonhomologation) of α‐Heteroatom‐substituted Acetates with Alkyl Formates: Utilization as (<i>Z</i>)‐Stereodefined Cross‐coupling Partners and Application to Concise Synthesis of Strobilurin A"}]},{"@id":"https://cir.nii.ac.jp/crid/1360848664437715840","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Asymmetric Total Syntheses of Two 3-Acyl-5,6- dihydro-2H-pyrones: (R)-Podoblastin-S and (R)- Lachnelluloic Acid with Verification of the Absolute Configuration of (−)-Lachnelluloic Acid"}]},{"@id":"https://cir.nii.ac.jp/crid/1390282680316630272","@type":"Article","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@language":"ja","@value":"キラルグアニジン触媒を活用する5<i>H</i>-オキサゾール-4-オンの求核付加反応：α-四置換ヒドロキシ酸誘導体の触媒的不斉合成法の開発"},{"@language":"en","@value":"Chiral Guanidines-catalyzed Nucleophilic Addition Reactions Using 5<i>H</i>-Oxazol-4-ones: Development of Catalytic Asymmetric Syntheses of Chiral α-Tetrasubstituted Hydroxycarboxylic Acid Derivatives"},{"@value":"キラルグアニジン触媒を活用する5H-オキサゾール-4-オンの求核付加反応 : α-四置換ヒドロキシ酸誘導体の触媒的不斉合成法の開発"},{"@language":"ja-Kana","@value":"キラルグアニジン ショクバイ オ カツヨウ スル 5H-オキサゾール-4-オン ノ キュウカク フカ ハンノウ : a-ヨン チカン ヒドロキシサン ユウドウタイ ノ ショクバイテキ フセイ ゴウセイホウ ノ カイハツ"}]},{"@id":"https://cir.nii.ac.jp/crid/2051151842066410112","@type":"Article","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Total synthesis of (±)-azaspirene via crystallization-induced diastereomer 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