has specified product has specified reactant has_intermediate carboxylic acid acyl chloride molecular skeleton insertion reaction Arndt-Eistert reaction A homologation reaction of a carboxylic acid to give the homologated carboxylic acid via acyl chloride and diazoketone intermediates. Arndt-Eistert synthesis RXNO RXNO:0000063 This is an insertion because the carbon atom is added between the R group and the carboxyl carbon in the starting material. https://www.rsc.org/Merck-Index/reaction/r10/ https://www.wikidata.org/wiki/Q137617