已开发出一种高效的钌 (II) 催化串联 C-C/C-N 键与芳基酰胺和 7-氮杂苯并降冰片二烯形成合成顺式稠合二氢苯并[ c ]菲啶酮。酰胺基团起导向基团和离去基团的作用,并提供了一种容易获得药学上有用的苯并[ c ]菲啶生物碱如尼替丁和法加罗宁类似物的途径。本方法与关于氮杂双环烯烃和芳族酰胺的各种官能团相容。氘标记研究提出并支持了涉及定向基团辅助 C-H 活化的反应机制。
Catalytic Direct β-Arylation of Simple Ketones with Aryl Iodides
作者:Zhongxing Huang、Guangbin Dong
DOI:10.1021/ja410389a
日期:2013.11.27
Herein we report a direct β-arylation of simple ketones with widely available aryliodides, combining palladium-catalyzed ketone oxidation, aryl-halide activation, and conjugate addition through a single catalytic cycle. Simple cyclic ketones with different ring-sizes, as well as acyclic ketones, can be directly arylated at the β-position with complete site-selectivity and excellent functional group
Palladium-catalyzed redox cascade for direct β-arylation of ketones
作者:Zhongxing Huang、Guangbin Dong
DOI:10.1016/j.tet.2018.03.017
日期:2018.6
design and development of two palladium-catalyzed redox cascade methods that enable direct β-arylation of ketones. Palladium-catalyzed ketone dehydrogenation, aryl-X bond activation and conjugate addition were merged into a redox-neutral catalytic cycle. Non-metal-based aryl electrophiles were used as both the oxidant and the aryl source. The β-arylation with aryliodides was achieved site-selectively
of iminyl radical‐triggered 1,5‐hydrogen atom transfer and (5+2) or (5+1) annulation processes, a series of structurally novel and interesting azepine and spiro‐tetrahydropyridine derivatives have been successfully prepared in moderate to good yields. This method utilizes FeCl2 as the catalyst and readily available oximes as five‐atom units, while showcasing broad substrate scope and good functional
Evidence and isolation of tetrahedral intermediates formed upon the addition of lithium carbenoids to Weinreb amides and N-acylpyrroles
作者:Laura Castoldi、Wolfgang Holzer、Thierry Langer、Vittorio Pace
DOI:10.1039/c7cc05215d
日期:——
The tetrahedralintermediates generated upon the addition of halolithium carbenoids (LiCH2X and LiCHXY) to Weinreb amides have been intercepted and fully characterized as O-TMS heminals. The commercially available N-trimethylsilyl imidazole is the ideal trapping agent whose employment, combined with a straightforward neutral Alox chromatographic purification, enables the isolation of such labile species
Phosphorus pentoxide for amide and peptide bond formation with minimal by-products
作者:Venkataramana Erapalapati、Umatai A. Hale、Nandita Madhavan
DOI:10.1016/j.tetlet.2019.151311
日期:2019.12
Phosphoruspentoxide and DMAP are used for amide bond formation from carboxylic acids and amines. Dipeptides and amides have been synthesized using this reagent in 42-77% yields and >99% ees. The protocol is attractive as it occurs at ambient temperature, the formation of organic by-products is minimal and the reagent can be readily quenched using water. Furthermore, excellent enantioselectivities