 The compound dirhodium tetraacetate is found to be especially effective.In a typical reaction ethyl diazoacetate (a well-known carbene precursor) and dirhodium tetraacetate react with hexane; the insertion into a C−H bond occurs 1% on one of the methyl groups, 63% on the alpha-methylene unit and 33% on the beta-methylene unit.The first such reaction was reported in 1981 by Teyssié 

In a general reaction mechanism for this reaction as proposed by Doyle in 1993  the metal that stabilizes the carbene, dissociates at the same time but not to the same degree as carbon–carbon bond formation and hydrogen atom migration.