p -Toluenesulfonic acid-catalyzed metal-free formal [4 + 1] heteroannulation via N H/O H/S H functionalization: One-pot access to 2-aryl/hetaryl/alkyl benzazole derivatives
concise and direct one-pot [4 + 1] synthetic strategy for the construction of 2-substituted benzazoles such as benzoxazoles and benzothiazoles has been disclosed in high yields (80–98%) by cascade coupling reaction of 2-amino(thio)phenols with β-oxodithioesters. The current approach enables NH/OH/SH functionalization in one-pot under solventless condition leading to diverse benzazoles without use of any
通过2-氨基(硫代)的级联偶联反应,已公开了一种高产率(80-98%)的简洁,直接的一锅[4 +1]合成策略,用于构建2-取代的苯并唑,如苯并恶唑和苯并噻唑酚与β-氧二硫代酯。目前的方法可以在无溶剂条件下在一锅中实现N H / O H / S H官能化,从而无需使用任何外部金属即可产生多种苯并恶唑。各种各样的2-氨基(硫代)酚和β-氧二硫代酯均具有出色的官能团耐受性,可用于该转化。此外,我们通过证明其与DNA拓扑异构酶II抑制剂的多样化多样化的相容性,抢占了这一新策略的广泛含义。
Access to Fully Substituted Thiazoles and 2,3-Dihydrothiazoles via Copper-Catalyzed [4 + 1] Heterocyclization of α-(<i>N</i>-Hydroxy/aryl)imino-β-oxodithioesters with α-Diazocarbonyls
An efficient chemoselective practical route to fully substituted thiazoles and 2,3-dihydrothiazoles has been devised by [4 + 1] heterocyclization of α-(N-hydroxy/aryl)imino-β-oxodithioesters with in situ generated Cu-carbenoids of diazocarbonyls. The α-(N-hydroxy/aryl)imino-β-oxodithioesters are readily accessible by the reaction of β-oxodithioesters with nitrous acid/nitrosoarenes. The overall transformation
Herein, we unveiled the novel approach for the synthesis of α-oxoketene S,S- and N,S-acetals employing a Mitsunobuprotocol. A wide range of alcohols has been successfully utilized, enabling great tolerability to this reaction. A diverse set of β-keto(dithioesters/thioamides) bearing various functional groups were found to be well suited substrates for this reaction, showing no obvious electronic effect
Dithioester-enabled chemodivergent synthesis of acids, amides and isothiazoles via C C bond cleavage and C O/C N/C S bond formations under metal- and catalyst-free conditions
作者:Sonam Soni、Suvajit Koley、Maya Shankar Singh
DOI:10.1016/j.tetlet.2017.05.064
日期:2017.6
operationally simple and user-friendly process to access privileged scaffolds such as acids, amides and isothiazoles has been devised employing β-ketodithioesters for the first time. Remarkably, the new protocol involves combination of CC bond cleavage and CO/CN/NS bond formations in one-pot. Aqueousammonia led to the formation of skeletally distinct amide and isothiazole, whereas aqueous NaOH enabled
首次设计了一种使用β-酮二硫酯的操作简单且用户友好的方法,可访问特权支架,例如酸,酰胺和异噻唑。值得注意的是,新方案涉及一锅中C C键断裂和C O / C N / N S键形成的组合。氨水导致骨骼上截然不同的酰胺和异噻唑的形成,而NaOH水溶液则使芳香酸的形成接近定量产率。这种实用的方法可以极大地简化简单分子的合成,具有高度的化学选择性,成本效益,可克量级,对水分不敏感以及具有很高的官能团相容性。
Metal- and Catalyst-Free, Formal [4 + 1] Annulation via Tandem C═O/C═S Functionalization: One-Pot Access to 3,5-Disubstituted/Annulated Isothiazoles
operationally simple and user-friendly new protocol for the synthesis of 3,5-disubstituted/annulated isothiazoles is devised utilizing β-ketodithioesters/β-ketothioamides and NH4OAc via C═O/C═S bond functionalizationunder metal- and catalyst-free conditions. The strategic [4 + 1] annulation initiated by NH4OAc is carbon-economic and relies on a sequential imine formation/cyclization/aerial oxidation cascade
利用β-酮二硫代酸酯/β-酮硫代酰胺和NH 4 OAc,通过在金属和催化剂下通过C / O / C functionalS键官能化,设计了一种操作简单且用户友好的新方法,用于合成3,5-二取代/环化异噻唑无条件。由NH 4 OAc引发的战略性[4 +1]环行是碳经济的,并依赖于在一个罐中形成连续C–N和S–N键的顺序亚胺形成/环化/航空氧化级联。在无毒条件下,具有出色的官能团耐受性的各种先前难以获得且具有合成挑战性的异噻唑均与该转化相容。该产品带有有用的合成手柄,可以进一步功能化。