{"title":"Visible-Light-Driven Racemization of 1,1′-Binaphthyl-2,2′-diamine (BINAM) Derivatives","authors":"Tatsuhiro Uchikura, Mikoto Sato, Yuki Kanno, Yukino Fukuda, Yurina Hara, Kota Yamamoto, Takahiko Akiyama","doi":"10.1021/acs.orglett.5c00162","DOIUrl":null,"url":null,"abstract":"We have achieved racemization of axially chiral diamines such as 1,1′-binaphthyl-2,2′-diamine (BINAM) by utilizing a visible-light-driven single-electron oxidation. BINAM derivatives were racemized at 30–40 °C via blue-light irradiation in the presence of an Ir(dF(CF<sub>3</sub>)ppy)<sub>2</sub>(dtbpy)PF<sub>6</sub> photocatalyst and <i>N,N-</i>dimethylaniline to afford racemic BINAM in 99% yield with <1% ee. Mechanistic studies demonstrated that the photocatalyst promoted the oxidation of BINAM to generate a radical cation species to facilitate racemization at low temperatures. Subsequent single-electron reduction by dimethylaniline afforded racemic BINAM. Dynamic kinetic resolution was also achieved with 80% enantioselectivity through a combination of kinetic resolution and racemization.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"49 1","pages":""},"PeriodicalIF":4.9000,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organic Letters","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.orglett.5c00162","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, ORGANIC","Score":null,"Total":0}
引用次数: 0
Abstract
We have achieved racemization of axially chiral diamines such as 1,1′-binaphthyl-2,2′-diamine (BINAM) by utilizing a visible-light-driven single-electron oxidation. BINAM derivatives were racemized at 30–40 °C via blue-light irradiation in the presence of an Ir(dF(CF3)ppy)2(dtbpy)PF6 photocatalyst and N,N-dimethylaniline to afford racemic BINAM in 99% yield with <1% ee. Mechanistic studies demonstrated that the photocatalyst promoted the oxidation of BINAM to generate a radical cation species to facilitate racemization at low temperatures. Subsequent single-electron reduction by dimethylaniline afforded racemic BINAM. Dynamic kinetic resolution was also achieved with 80% enantioselectivity through a combination of kinetic resolution and racemization.
期刊介绍：
Organic Letters invites original reports of fundamental research in all branches of the theory and practice of organic, physical organic, organometallic,medicinal, and bioorganic chemistry. Organic Letters provides rapid disclosure of the key elements of significant studies that are of interest to a large portion of the organic community. In selecting manuscripts for publication, the Editors place emphasis on the originality, quality and wide interest of the work. Authors should provide enough background information to place the new disclosure in context and to justify the rapid publication format. Back-to-back Letters will be considered. Full details should be reserved for an Article, which should appear in due course.
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