A novel approach to 2,5-disubstituted 1,3,4-oxadiazoles derivatives via a decarboxylative cyclization reaction by photoredox catalysis between commercially available α-oxocarboxylic acids and hypervalent iodine(III) reagent is described. This powerful transformation involves the coupling reaction between two different kinds of radical species and the formation of C−N and C−O bonds.

An efficient synthesis of a variety of [1,2,3]­triazolo-[1,5-a]­quinoxalin-4­(5H)-ones via a [3 + 2] cyclization reaction by photoredox catalysis between quinoxalinones and hypervalent iodine­(III) reagents is reported. A range of quinoxalinones and hypervalent iodine­(III) reagents were tolerated well. This cyclization reaction allows access to structurally diverse [1,2,3]­triazolo-[1,5-a]­quinoxalin-4­(5H)-ones in moderate to good yields.

A photocatalyzed cascade double C−C formation via sp 2 C−H bond activation of diarylamines with hypervalent iodine diazo reagents was developed. A variety of diarylamines and hypervalent iodine(III) reagents were tolerated well, and a range of substituted acridines with yields ranging from moderate to excellent was provided efficiently. The protocol introduces diazo groups onto diarylamines and enables subsequent late-stage assembly point functionalization with the diazonium structure, forming two new C−C bonds in a sequential fashion.

An efficient synthesis of a variety of 2,5-disubstituted 1,3,4-oxadiazole derivatives via a cyclization reaction by photoredox catalysis between aldehydes and hypervalent iodine­(III) reagents is described. The reaction proceeds under mild conditions and affords various target compounds in excellent yields. The commercially available aldehydes without preactivation and a simple visible-light-promoted procedure without any catalysts make this strategy an alternative to the conventional methods.