Preparation of anthranils via chemoselective oxidative radical cyclization of 3-(2-azidoaryl) substituted propargyl alcohols

In presence of K2S2O8 and HOAc, propargyl alcohols can go oxidative radical cyclizations to give a pool of anthranils. Excellent chemoselectivity was seen, and the synthesized anthranils can be employed as N-nucleophiles in various transformations.

Peroxide-Mediated Oxidative Radical Cyclization to the Quinazolinone System: Efficient Syntheses of Deoxyvasicinone, Mackinazolinone and (±)-Leucomidine C

An efficient protocol for obtaining fused quinazolinones through an oxidative free-radical cyclization under metal- and tin-free conditions is described. The oxidative cyclization of various N-3-ω-iodoalkyl derivatives to provide tricyclic systems using dicumyl peroxide as the sole reagent is studied. The method then is employed for the syntheses of 5-, 6-, and 7-membered fused quinazolinone analogues, including the natural products deoxyvasicinone and mackinazolinone. A xanthate-based oxidative radical cascade addition/cyclization process that allows the production of new menthol- and testosterone-quinazolinone conjugates, as well as the first total synthesis of leucomidine C, are also reported.

Mn-mediated oxidative radical cyclization of 2-(azidomethyl)phenyl isocyanides with carbazate: access to quinazoline-2-carboxylates

Mn-TBHP mediated oxidative radical cyclization of 2-(azidomethyl)phenyl isocyanides using methyl carbazate has been described.

Metal-free, visible-light-promoted oxidative radical cyclization of N-biarylglycine esters: one-pot construction of phenanthridine-6-carboxylates in water

A metal-free, visible-light (blue LED: hν = 425 ± 15 nm) photoredox-catalyzed intramolecular cyclization reaction of N-biarylglycine esters to phenanthridine-6-carboxylates in water under an open air atmosphere at ambient conditions has been developed.

Free Radical Cyclization of N-Arylacrylamides: Mild and Facile Synthesis of 3-Thiocyanato Oxindoles

A novel and convenient oxidative radical cyclization of N-substituted N-arylacrylamides for the synthesis of 3-thiocyanated oxindoles has been developed by using AgSCN and K2S2O8 as the radical source. This process allows a consistent and convenient access to SCN-containing heterocycles bearing a broad range of functional groups in good to excellent yields (up to 91%). Moreover, the use of inexpensive and readily available starting materials, operational simplicity, and excellent functional group tolerance makes this protocol practically attractive.

Transition-metal-free and organic solvent-free conversion of N-substituted 2-aminobiaryls into corresponding carbazoles via intramolecular oxidative radical cyclization induced by peroxodisulfate

An atom-economical and environmentally benign synthesis of N-substituted carbazoles is described. This methodology afforded products in 90–120 minutes.