Propynal Equivalents and Diazopropyne: Synthesis of All Mono‐ 13 C Isotopomers

Mechanistic and spectroscopic investigations of reactive C 3 H 2 hydrocarbons necessitated the preparation of diazopropyne isotopomers bearing mono‐ 13 C substitution at each of the three unique positions. The diazo compounds and their tosylhydrazone precursors were prepared from the mono‐ 13 C isotopomers of propynal (in the form of either the aldehyde or the diethyl acetal). The introduction of 13 C‐labeling at either alkyne position in propynal utilized the Corey – Fuchs procedure for chain homologation.