Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India.
J Org Chem. 2023 Jul 7;88(13):8480-8492. doi: 10.1021/acs.joc.3c00455. Epub 2023 May 25.
α-Branched amines are key motifs that exist in a plethora of natural products and pharmaceuticals. Herein we disclose the first convergent synthesis of α-branched amines bearing β-carbonyl in isoindolinones by employing tertiary amides and alkyl esters as benign electrophile sources. The reaction proceeds by the direct aroylation of a C()-H carbon adjacent to the nitrogen atom in core isoindolinones. Several amides and esters were screened to choose the potential acyl source for the substrate scope. The reaction is carried out with a repertoire of substrates under mild conditions and shows high functional group compatibility. Remarkably the reaction is amenable to organometallic ferrocenyl ester and indole methyl esters bearing an acidic NH moiety. Strikingly no trace of amidation product is observed. In particular α-branched amines bearing β-carbonyl synthesized from indole methyl esters are considered important targets, as both motifs are prevalent in many drugs. This protocol is scalable, and products obtained from indole methyl esters show strong solid-state emission properties which are complementary with DFT calculations.
α-支链胺是存在于大量天然产物和药物中的关键结构基序。本文首次披露了通过使用叔酰胺和烷基酯作为良性亲电试剂源,在异吲哚啉酮中承载β-羰基的α-支链胺的会聚合成。该反应通过直接芳构化在核心异吲哚啉酮中紧邻氮原子的 C()-H 碳进行。筛选了几种酰胺和酯以选择潜在的酰基源以扩大底物范围。该反应在温和条件下进行,具有多种底物,显示出高官能团相容性。值得注意的是,该反应适用于含有酸性 NH 部分的有机金属二茂铁酯和吲哚甲酯。引人注目的是,没有观察到酰胺化产物的痕迹。特别是从吲哚甲酯合成的含有β-羰基的α-支链胺被认为是重要的目标,因为这两个基序在许多药物中都很普遍。该方案是可扩展的,并且从吲哚甲酯获得的产物在固态下具有很强的发射性质,这与 DFT 计算互补。