Xia Hanyu, Jiang Xingni, Lin Di, Zhang Shaoping, Yu Zhiying, Wu Xianqing, Qu Jingping, Chen Yifeng
Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science & Technology, 130 Meilong Road, Shanghai 200237, China.
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
J Am Chem Soc. 2024 Oct 3. doi: 10.1021/jacs.4c10809.
The Barbier reaction is a reductive-type addition of an aldehyde or ketone with an organic electrophile in the presence of a terminal metal reductant, providing a straightforward and efficient method for carbon-carbon bond formation. This reaction possesses the advantage of circumventing the preparation of moisture- and air-sensitive organometallic reagents. However, the catalytic Barbier reaction of ketones to construct tetrasubstituted stereogenic centers is largely underdeveloped, despite its great potential for accessing synthetically challenging chiral tertiary alcohol. Particularly, the leveraging of unactivated alkyl electrophiles as coupling components is still rarely exploited. Herein, we disclose a photoredox-assisted cobalt-catalyzed asymmetric alkylative Barbier-type addition reaction of ketones to address the aforementioned challenges, thereby allowing for the construction of highly congested tetrasubstituted carbon centers. The alkyl addition fragments could be either readily accessible unactivated alkyl halides or redox-active esters generated through a decarboxylative pathway. Both types of alkyl electrophiles include primary, secondary, and tertiary ones, thus affording diverse enantioenriched tertiary alcohols with a broad substrate scope. This enantioselective protocol is applied for the expedient synthesis of core structure of , a very recent FDA-approved drug in 2024. The newly developed bisoxazolinephosphine (NPN) ligand enables high enantioselectivity in this asymmetric reductive addition process.
巴比耶反应是在末端金属还原剂存在下醛或酮与有机亲电试剂的还原型加成反应,为碳-碳键形成提供了一种直接有效的方法。该反应具有避免制备对水分和空气敏感的有机金属试剂的优点。然而,尽管酮的催化巴比耶反应在构建四取代立体中心方面具有很大潜力,可用于合成具有挑战性的手性叔醇,但目前该领域仍未得到充分发展。特别是,利用未活化的烷基亲电试剂作为偶联组分的情况仍然很少被探索。在此,我们报道了一种光氧化还原辅助的钴催化的酮的不对称烷基化巴比耶型加成反应,以应对上述挑战,从而实现高度拥挤的四取代碳中心的构建。烷基加成片段可以是易于获得的未活化烷基卤化物或通过脱羧途径生成的氧化还原活性酯。这两种类型的烷基亲电试剂都包括伯、仲和叔烷基亲电试剂,因此能够提供多种对映体富集的叔醇,底物范围广泛。这种对映选择性方法被应用于2024年最近获得美国食品药品监督管理局批准的一种药物核心结构的便捷合成。新开发的双恶唑啉膦(NPN)配体在这种不对称还原加成过程中实现了高对映选择性。