- Versatile cp*Rh(III)-Catalyzed selective ortho-Chlorination of arenes and heteroarenes
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The ortho- and monoselective Cp*Rh(III)-catalyzed chlorination of a broad range of benzene derivatives and electron-rich heterocycles under mild reaction conditions is reported. Inexpensive and commercially available N-chloro-imides could be used as chlorinating agents in as low as substoichiometric quantities. Furthermore, two different reaction protocols were developed to allow for the use of substrates with various electronic properties and enable selective chlorination of a broad range of structural motifs. For electron-rich substrates, the reported protocols enable a perfectly regio-switchable and efficient direct chlorination.
- Lied, Fabian,Lerchen, Andreas,Knecht, Tobias,Mück-Lichtenfeld, Christian,Glorius, Frank
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- Lipshutz-type bis(amido)argentates for directed: Ortho argentation
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Bis(amido)argentate (TMP)2Ag(CN)Li2 (3, TMP-Ag-ate; TMP = 2,2,6,6-tetramethylpiperidido) was designed as a tool for chemoselective aromatic functionalization via unprecedented directed ortho argentation (DoAg). X-Ray crystallographic analysis showed that 3 takes a structure analogous to that of the corresponding Lipshutz cuprate. DoAg with this TMP-Ag-ate afforded multifunctional aromatics in high yields in processes that exhibited high chemoselectivity and compatibility with a wide range of functional groups. These included organometallics- A nd transition metal-susceptible substituents such as methyl ester, aldehyde, vinyl, iodo, (trifluoromethanesulfonyl)oxy and nitro groups. The arylargentates displayed good reactivity with various electrophiles. Chalcogen (S, Se, and Te) installation and azo coupling reactions also proceeded efficiently.
- Tezuka, Noriyuki,Hirano, Keiichi,Peel, Andrew J.,Wheatley, Andrew E. H.,Miyamoto, Kazunori,Uchiyama, Masanobu
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p. 1855 - 1861
(2020/03/03)
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- Amide Effects in C?H Activation: Noncovalent Interactions with L-Shaped Ligand for meta Borylation of Aromatic Amides
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A new concept for the meta-selective borylation of aromatic amides is described. It has been demonstrated that while esters gave para borylations, amides lead to meta borylations. For achieving high meta selectivity, an L-shaped bifunctional ligand has been employed and engages in an O???K noncovalent interaction with the oxygen atom of the moderately distorted amide carbonyl group. This interaction provides exceptional control for meta C?H activation/borylation.
- Bisht, Ranjana,Hoque, Md Emdadul,Chattopadhyay, Buddhadeb
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p. 15762 - 15766
(2018/11/10)
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- Nickel or phenanthroline mediated intramolecular arylation of sp 3 C-H bonds using aryl halides
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The development of the intramolecular arylation of sp3 C-H bonds adjacent to nitrogen using aryl halides is described. Arylation was accomplished using either Ni(COD)2 or 1,10-phenanthroline in substoichiometric amounts, and the reaction conditions were applied to a variety of electronically differentiated benzamide substrates. Preliminary studies suggest a mechanism involving aryl and alkyl radical intermediates.
- Wertjes, William C.,Wolfe, Lydia C.,Waller, Peter J.,Kalyani, Dipannita
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supporting information
p. 5986 - 5989
(2014/01/06)
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- Generation of an aromatic amide-derived phosphane (Aphos) library by self-assisted molecular editing and applications of Aphos in room-temperature Suzuki-Miyaura reactions
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Aromatic amide-derived phosphanes (Aphos) are hemilabile P,O-coordinating ligands, which, when combined with a Pd precursor, yield a promising precatalyst system for Suzuki-Miyaura cross-coupling reactions. A focused library of Aphos ligands has been constructed for structural optimization, with the target of improving catalytic efficacy. By using microwave irradiation at accurately regulated temperature, an expeditious and reproducible one-pot synthesis and screening protocol was designed and experimentally validated. The success is based on a unique self-assisted molecular editing (SAME) process in which both the substrate and the product molecules catalyze formation of the product. Thus, starting from a 4-chlorobenzamide-derived Aphos as the substrate, parallel reactions with a selected set of arylboronic acids, in the absence of an added external phosphane ligand to Pd, produced a family of structurally edited Aphos ligands. The resultant reaction mixture containing the new Aphos, the Pd species, and the base could be used for in situ screening of the Aphos efficacy in a reference Suzuki-Miyaura coupling reaction. The structures of all Aphos ligands were characterized by 31P NMR spectroscopy and their catalytic profiles in the reference reaction were evaluated by HPLC analysis. These data allowed the identification of an efficient Aphos ligand, capable of promoting room-temperature Suzuki-Miyaura coupling of unactivated and sterically hindered aryl chlorides with arylboronic acids under mildly basic conditions.
- Dai, Wei-Min,Li, Yannian,Zhang, Ye,Yue, Congyong,Wu, Jinlong
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supporting information; experimental part
p. 5538 - 5554
(2009/05/30)
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- The halogenation of some benzamides takes place preferentially at the ortho,para positions
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The orientation of chlorination and bromination of N,N-disubstituted benzamides in aqueous acetic acid is strongly influenced by the nature of the alkyl groups at the nitrogen atom. With large groups, the halogenation takes place fairly selectively at the ortho/para positions.
- Dong, Chang-Zhi,Julia, Marc,Tang, Jie
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p. 1689 - 1696
(2007/10/03)
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