Rhodium-catalyzed C–H functionalization with N-acylsaccharins

Abstract

A rhodium-catalyzed C-H functionalization with activated amides by decarbonylation has been developed. Notably, this is the first C-H arylation employing N-acylsaccharins as coupling partners to give biaryls in good to excellent yields. The highlight of the work is the high tolerance of functional groups such as formyl, ester, and vinyl and the use of a removable directing group.

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

“…Inspired by Szostak's arylation method using aromatic amides as arylation reagents ( Scheme 109A ), Zeng performed the arylation of indoles (and benzo[ h ]quinoline) using N -acyl saccarines as reagent under similar conditions ( Scheme 109I ). 646 The use of boronic acids for indole arylation was instead reported by Kapur. This method provides good substrate scope and yields, although requiring stoichiometric amounts of both Cu and Ag ( Scheme 109J ).…”

Homogeneous Gold‐Catalyzed Cyclization Reactions of Alkynes with N‐ and S‐Nucleophiles

“…Wu and co‐workers produced pyrazolo[1,5‐ a ]pyridines 217 ­ via an Au(I)‐catalyzed cyclization of alkynylpyrazoles 215 (Scheme ) 135. Salts of Pt, Pd, Cu, Ag and Zn were evaluated for the ring closure as well but conversion was incomplete or required reflux in CH 3 CN for prolonged periods of time.…”

“…A combination of PPh 3 AuCl and AgSbF 6 resulted in full conversion after 5 h at room temperature. Iodine‐mediated cyclization was possible as well and resulted in iodinated pyrazolo[1,5‐ a ]pyridines which are excellent substrates for further derivatization through cross‐coupling strategies 135. Propargylic enamines were converted into pyridines using NaAuCl 4 ⋅2 H 2 O and PPh 3 AuOTf by Arcadi and Wang, respectively 136,137…”

Palladium-Catalyzed Room Temperature Acylative Cross-Coupling of Activated Amides with Trialkylboranes

“…However, the synthetic utility of amides as an acyl source had remained underdeveloped until the seminal publications in 2015 independently from Garg [ 1 ], Szostak [ 2 ], and ourselves [ 3 ], taking advantage of palladium or nickel catalysis for cleavage of electronically or sterically activated amide C-N bond, and formation of new carbon-carbon or carbon-oxygen bonds. In the past three years, many efforts have been made to expand the scope of amide counterparts, developing a variety of activated amides suitable for the acylative cross-coupling, e.g., N -acyl imides [ 4 , 5 , 6 ], N -Boc and N -Ts/Ms amides [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ], N -acylsaccharins [ 16 , 17 , 18 , 19 , 20 ], and amides of heteroaromatic compounds [ 21 , 22 ]. Comparably, the carbon-centered nucleophile counterparts are still rather undeveloped, in particular, with respect to alkyl ones, although alkyl ketones have been widely found in biologically important molecules and synthetic building blocks for fine chemicals.…”