text: The Büchner–Curtius–Schlotterbeck reaction can be used to facilitate one carbon ring expansions when the substrate ketone is cyclic. For instance, the reaction of cyclopentanone with diazomethane forms cyclohexanone (shown below).  The Büchner ring expansion reactions utilizing diazoalkanes have proven to be synthetically useful as they can not only be used to form 5- and 6-membered rings, but also more unstable 7- and 8-membered rings.
  An acyl-diazomethane can react with an aldehyde to form a β-diketone in the presence of a transition metal catalyst (SnCl in the example shown below). β-Diketones are common biological products, and as such, their synthesis is relevant to biochemical research.  Furthermore, the acidic β-hydrogens of β-diketones are useful for broader synthetic purposes, as they can be removed by common bases.
  Acyl-diazomethane can also add to esters to form β-keto esters, which are important for fatty acid synthesis. As mentioned above, the acidic β-hydrogens also have productive functionality.
  The Büchner–Curtius–Schlotterbeck reaction can also be used to insert a methylene bridge between a carbonyl carbon and a halogen of an acyl halide.  This reaction allows conservation of the carbonyl and halide functionalities.
  It is possible to isolate nitrogen-containing compounds using the Büchner–Curtius–Schlotterbeck reaction.  For example, an acyl-diazomethane can react with an aldehyde in the presence of a DBU catalyst to form isolable α-diazo-β-hydroxy esters (shown below).