Synthesis of <i>o</i>-(Dimethylamino)aryl Ketones, Acridones, Acridinium Salts, and 1<i>H</i>-Indazoles by the Reaction of Hydrazones and Arynes
作者:Anton V. Dubrovskiy、Richard C. Larock
DOI:10.1021/jo302378w
日期:2012.12.21
A novel, efficient route to biologically and pharmaceutically important o-(dimethylamino)aryl ketones, acridones, acridinium salts, and 1H-indazoles has been developed starting from readily available hydrazones of aldehydes and o-(trimethylsilyl)aryl triflates. The reaction proceeds through arynes under mild conditions, tolerates a wide range of functional groups, and provides the final products in
facile synthesis of 1H-indazoles featuring a Cu(OAc)2-catalyzed N–N bond formation using oxygen as the terminal oxidant is described. The reaction of readily available 2-aminobenzonitriles with various organometallic reagents led to o-aminoaryl N–H ketimine species. The subsequent Cu(OAc)2-catalyzed N–N bond formation in DMSO under oxygen afforded a wide variety of 1H-indazoles in good to excellent
An efficient and mild protocol for regioselective synthesis of N-Nitroso aryl ketones by palladium-catalyzed directacylation of arenes using N-Nitroso as directing groups is described. This reaction proceeded smoothly and could tolerate a variety of functional groups. Moreover, this chemistry offers a convenient access to a range of indazoles.
Synthesis of 3-aryl-1H-indazoles via iridium-catalysed C–H borylation and Suzuki–Miyaura coupling
作者:Ben A. Egan、Paul M. Burton
DOI:10.1039/c4ra04235b
日期:——
The regioselective iridium-catalysed C3-borylation of 1H-indazoles has been achieved. Subsequent SuzukiâMiyaura coupling of the boronate esters with aryl chlorides, bromides and iodides affords 3-aryl-1H-indazoles in good yields.
The [4+1] cycloaddition reaction of bifunctional amino reagents has been achieved with in situ formed aza‐ortho‐quinonemethides. Specifically, N‐(tosyloxy)carbamates were used as an N1 synthon and bifunctional amino reagents for this transformation, which provides a metal‐free, catalyst‐free, and oxidant‐free strategy to form nitrogen‐nitrogen bonds.