Structure Ligation Relationship of Amino Acids for the Selective Indole C−H Arylation Reaction: L‐Aspartic acid as Sustainable Alternative of Phosphine Ligands
The S tructure L igation R elationship (SLR) of free amino acids (AAs) under Pd‐catalysis were examined for the chemo‐ and regio‐selective indole C−H arylation reactions. While the majority of AAs were minor or ineffective, the L‐aspartic acid (L‐Asp) stands out promising to deliver high‐value C3‐arylated indoles with excellent chemo‐ (C vs N) and regioselectivity (C3 vs C2) with high functional group
该小号tructure大号igation ř elationship(SLR)的游离氨基酸(AAS)下的Pd催化检查用于化疗和区域选择性的吲哚C-H芳基化反应。尽管大多数AA很少或无效,但是L-天冬氨酸(L-Asp)有望提供具有高化学(C vs N)和区域选择性(C3 vs C2)的高价值C3芳基吲哚功能组耐受性。因此,该方案为吲哚C3-H芳基化反应提供了基于膦的配体的经济高效且可持续的替代品。初步机械调查建议-NH的同时参与2,α-CO 2 H,和β-CO 2L‐Asp的H功能及其连接效率至关重要。所开发的催化系统与用于3芳基吲哚化学选择性合成的串联脱羧/芳基化程序兼容。
Copper-Catalyzed Direct Synthesis of 3-Arylindoles
作者:Siva Murru、August A. Gallo、Radhey S. Srivastava
DOI:10.1002/ejoc.201001745
日期:2011.4
A direct method for the preparation of various 3-arylindoles from their corresponding nitrosoarenes has been developed. Various substituted nitrosoarenes and alkynes were employed to obtain substituted indoles by using a CuII–Cu0 catalytic system. This is a two-step method that involves annulation of the nitrosoarene and alkyne followed by deoxygenation to give 3-arylindoles.
The direct C3-arylation of N-unsubstituted indoles with arylchlorides and triflates has been realized using a palladium–dihydroxyterphenylphosphine (DHTP) catalyst. The site selectivity is different from that obtained with other structurally related ligands. This unique feature of the DHTP ligand is attributed to complex formation between the lithium salts of the ligand and the indole. The method