1448724-97-7Relevant articles and documents
Cobalt(III)-catalyzed synthesis of indazoles and furans by C-H bond functionalization/addition/cyclization cascades
Hummel, Joshua R.,Ellman, Jonathan A.
, p. 490 - 498 (2015)
The development of operationally straightforward and cost-effective routes for the assembly of heterocycles from simple inputs is important for many scientific endeavors, including pharmaceutical, agrochemical, and materials research. In this article we describe the development of a new air-stable cationic Co(III) catalyst for convergent, one-step benchtop syntheses of N-aryl-2H-indazoles and furans by C-H bond additions to aldehydes followed by in situ cyclization and aromatization. Only a substoichiometric amount of AcOH is required as an additive that is both low-cost and convenient to handle. The syntheses of these heterocycles are the first examples of Co(III)-catalyzed additions to aldehydes, and reactions are demonstrated for a variety of aromatic, heteroaromatic, and aliphatic derivatives. The syntheses of both N-aryl-2H-indazoles and furans have been performed on 20 mmol scales and should be readily applicable to larger scales. The reported heterocycle syntheses also demonstrate the use of directing groups that have not previously been applied to Co(III)-catalyzed C-H bond functionalizations. Additionally, the synthesis of furans demonstrates the first example of Co(III)-catalyzed functionalization of alkenyl C-H bonds.
Rhodium(III)-catalyzed alkenyl C-H bond functionalization: Convergent synthesis of furans and pyrroles
Lian, Yajing,Huber, Tatjana,Hesp, Kevin D.,Bergman, Robert G.,Ellman, Jonathan A.
supporting information, p. 629 - 633 (2013/02/23)
Ring in the new: A new annulation for the efficient synthesis of substituted furans and pyrroles is reported. The RhIII-catalyzed reaction of O-methyl α,β-unsaturated oximes with aldehydes and N-tosyl imines affords secondary alcohol and amine intermediates, respectively. Cyclization and aromatization occurs under the reaction conditions to provide access to biologically relevant furans and pyrroles in good yields. Cp=C5Me5, DCE=1,2-dichloroethane, THF=tetrahydrofuran. Copyright
