Nickel-Catalyzed Cross-Coupling of Chromene Acetals and Boronic Acids
作者:Thomas J. A. Graham、Abigail G. Doyle
DOI:10.1021/ol300364s
日期:2012.3.16
nes is described. Under base-free conditions, readily accessible 2-ethoxy-2H-chromenes undergo Csp3–O activation and Csp3–C bond formation in the presence of an inexpensive nickel catalyst and boronicacids. This new strategy enables broad access to 2-substituted-2H-chromenes and has been applied to the late-stage incorporation of complex molecules, including the pharmaceuticals loratidine and indomethacin
描述了一种用于合成 2-芳基-和杂芳基-2 H-色烯的模块化和高效方案。在无碱条件下,容易获得的 2-乙氧基-2 H-色烯在廉价的镍催化剂和硼酸存在下经历 C sp 3 -O 活化和 C sp 3 -C 键形成。这种新策略可以广泛使用 2-取代-2 H-色烯,并已应用于复杂分子的后期掺入,包括药物氯雷他定和吲哚美辛甲酯。
Copper-catalyzed oxidative cross-dehydrogenative coupling of 2<i>H</i>-chromenes and terminal alkynes
作者:Fei Yang、Yangshan Li、Paul E. Floreancig、Xiaoyan Li、Lei Liu
DOI:10.1039/c8ob00949j
日期:——
An efficient copper-catalyzedcross-dehydrogenativecoupling of 2H-chromenes and terminal alkynes mediated by DDQ has been established. A protic additive, EtOH, proved to be crucial for harmonizing the oxidation with a subsequent alkynylation step by retaining the oxidation state of an oxocarbenium ion in the form of acetal. The CDC reaction exhibits a good substrate scope, with a range of terminal
Brønsted Acid/Lewis Acid Cooperatively Catalyzed Addition of Diazoesters to 2<i>H</i>-Chromene Acetals
作者:Yi Luan、Yue Qi、Hongyi Gao、Qianqian Ma、Scott E. Schaus
DOI:10.1002/ejoc.201403043
日期:2014.11
A novel Brønsted acid/Lewisacid dual catalyst system has been developed to promote an efficient C-C bond formation between a range of oxocarbenium precursors derived from chromene acetals and ethyldiazoacetate. The reaction proceeds under mild conditions and is tolerant of common functionalized 2H-chromene and isochromene acetals. In addition, an asymmetric variant of diazoacetate addition towards
已开发出一种新型布朗斯台德酸/路易斯酸双催化剂体系,以促进一系列衍生自色烯缩醛和重氮乙酸乙酯的氧代碳鎓前体之间有效形成 CC 键。该反应在温和的条件下进行,并且可以耐受常见的官能化 2H-色烯和异色烯缩醛。此外,还描述了重氮乙酸酯加成到 2H-色烯缩醛的不对称变体。继续研究包括对形成重氮酯取代的 2H-色烯的不对称诱导的进一步优化。
Catalyst‐Free Synthesis of α‐Functionalized 2
<i>H</i>
‐Chromenes in Water: A Tandem Self‐Promoted
<i>pseudo</i>
‐Substitution and Decarboxylation Process
作者:Chunhui Jiang、Yayun Chen、Hongkui Zhang、Jian‐Ping Tan、Tianli Wang
DOI:10.1002/asia.201900641
日期:2019.9.2
protocol was also demonstrated by the scale-up synthesis and versatile conversions of the title product into other useful compounds. In addition, control experiments indicated that water was essential for the reactivity. Mechanistic studies further revealed that the reaction proceeded through a self-promoted tandem pseudo-substitution and decarboxylation process.