Di‐tert Butyl Peroxide‐Promoted Sequential Methylation and Intramolecular Aromatization of Isonitriles

Abstract

The di-tert butyl peroxide (DTBP)-promoted sequential reaction of isonitriles is developed, leading to 6-methylphenanthridine derivatives in moderate to excellent yields. DTBP served as both promoter and methyl source. The procedure proceeds through the addition of a methyl radical derived from the peroxide to the isonitrile followed by aromatic homolytic cyclization. It tolerates a series of functional groups, such as fluoro, chloro, acetyl, methoxycarbonyl, cyano and trifluoromethyl.

Iron‐Catalyzed Radical Cleavage/C−C Bond Formation of Acetal‐Derived Alkylsilyl Peroxides

“…The reaction of 1 a with 2 a could be conducted on a gram scale, although the product 3 aa was obtained in slightly lower yield (entry 1). The reaction of other carbon electrophiles, such as acrylamide 2 b , isocyanide 2 c with 1 a successfully afforded the oxindole derivative 3 ab and phenanthridine derivative 3 ac , respectively (entries 2 and 3). In addition, the reaction with pharmaceutically important quinoxaline derivative 2 d was also possible (entry 4).…”

Direct Oxidative Cross‐Coupling of Toluene Derivatives and N‐Acyl‐2‐aminoacetophenones

“…Other commercially available oxidants including TBHP, CHP, TBPB, DCP and BPO were also tested and DTBP remained as the best one (Table , entries 7–11). To promote the reaction, catalytic amounts (20 mol%) of I 2 , CuCl, and FeCl 2 were added to the reaction but led to poor yields (Table , entries 12–14). On the basis of these results, entry 2 represents the best conditions.…”

Recent Advances in Transition Metal‐Catalyzed Methylation Reactions

“…Finally, the single electron transfer reaction between intermediate B and the tert ‐butoxy radical or Fe(III) species affords the desired product to complete the catalytic cycle. After that, the same group reported an iron‐catalyzed sequential methylation and aromatization of isonitriles for the synthesis of 6‐methylphenanthridine derivatives (Scheme ) 44. This new reaction involves the addition of a methyl radical derived from the tert ‐butyl peroxide to the isonitrile, followed by an aromatic homolytic cyclization.…”