Synthesis of 6-acyl phenanthridines by oxidative radical decarboxylation–cyclization of α-oxocarboxylates and isocyanides

Abstract

A silver catalysed synthesis of 6-acyl phenanthridines by oxidative radical decarboxylation-cyclization of α-oxocarboxylates and isocyanides was developed. This reaction provided a novel method to realize C1 insertion via a radical process and various functional groups were well-tolerated.

Visible-light-mediated trifluoroethylation of 2-isocyanobiaryl with trifluoroethyl iodide: Synthesis of 6-trifluoroethyl-phenanthridines

“…On the basis of the experimental observation and literatures [44][45][46][47][48][49][50][51][52][53] …”

“…For instance, Carreira reported a cobaltcatalyzed photochemical synthesis of allylic trifluoromethanes from styrene derivatives using 2,2,2-trifluoroethyl iodide [38]. On the basis of this work and in connection with our interest radical cyclizations [39][40][41][42][43], we communicate herein our recent studies on the visible-light-promoted trifluoroethylation of 2-isocyanobiaryl using the cheap and available reagent CF 3 CH 2 I as the source of the CH 2 CF 3 group to afford 6-trifluoroethyl-phenanthridine derivatives (Scheme 1) [44][45][46][47][48][49][50][51][52][53].…”

Palladium-Catalyzed Decarboxylative Csp2–Csp2 Cross-Coupling Reactions: An Efficient Route for Synthesis of Azaisoflavone Derivatives

“…In addition, the decarboxylative couplings between carboxylic acids and phenylboronic acids for the Pd-or Ni-catalyzed C-C bonds formation have also been reported [30][31][32][33]. Recently, transition-metal-catalyzed C-H activation/decarboxylative couplings for the formation of Csp 2 -Csp 2 bond have successfully been investigated [34]. Furthermore, extrusion of CO 2 as the side product during the reaction is considered to be environmentally benign and requires no more special separation procedures.…”

Visible‐Light‐Induced, Manganese‐Catalyzed Tandem Cyclization of 2‐Biphenyl Isocyanides with Cyclopropanols for the Synthesis of 6‐β‐Ketoalkyl Phenanthridines

“…[14] Therefore, the synthesis of phenan-thridine derivatives is great significance and has drawn much attention in recent years. A great number of radical precursors have been investigated to provide various 6-position functionalized phenanthridines, including alkylation, [12c,15] fluoroalkylation, [16] arylation, [17] phosphorylation, [18] aroylation, [19] carboxylation, [20] and silylation, [21] etc. For example, a range of 6alkylated phenanthridines were prepared through oxidative cyclization of 2-biphenyl isocyanides with various alkyl radical precursors (Scheme 1a), [12c,15] such as alkyl boronic acids, alkyl bromides, ethers, alkanes, alcohols, alkyl acyl peroxides, 1,3dicarbonyl compounds, alkyl trifluoroborates, CF 3 reagents, etc.…”