Boron Chelates Derived from N-Acylhydrazones as Radical Acceptors: Photocatalyzed Coupling of Hydrazones with Carboxylic Acids

Difluoroboryl complexes obtained from N-acyl hydrazones upon brief treatment with boron trifluoride and allylic silane serve as efficient acceptors of alkyl radicals. The reaction of the boryl chelates with carboxylic acids in the presence of an acridine-type photocatalyst leading to N-acyl hydrazides is described. The efficiency of addition at the C=N bond of the chelates is determined by the formation of a nitrogen-centered radical stabilized by the boron-containing heterocyclic ring.

Automated summary

Difluoroboryl complexes derived from N-acyl hydrazones are efficient acceptors of alkyl radicals, reacting with carboxylic acids under the influence of an acridine-type photocatalyst to form N-acyl hydrazides. The efficiency of addition at the C=N bond of the chelates is determined by the stabilization of a nitrogen-centered radical by the boron-containing heterocyclic ring.