Synthesis of cyclopropaneacetylene by a one-pot process

A process for the preparation of cyclopropaneacetylene comprising the steps of:

• (a) reacting a ketophosphonate compound of Formula I,
• with a diazo-transfer reagent, [(R*)2N]3P+N3X−, wherein R* is C1-C5 alkyl and X− is halide, in the presence of a catalytic amount of a first non-nucleophilic base in an aprotic solvent to generate a reaction mixture containing ketodiazophosphonate compound of Formula II;
• wherein R1 and R2 substituents in Formulae I and II independently are:
• C1-C6 alkyl or aryl, wherein aryl is defined as phenyl or naphthyl which is unsubstituted or substituted with one or two substituents selected from the group consisting of:
• Cl, F, Br, I, (C1-C4)-alkyl, —O—(C1-C4)-alkyl, —NO2, —OH, CF3, (C1-C4)-alkoxy, S(O)x—(C1-C4)-alkyl wherein x is 0, 1, or 2, —N(R)2, —COOR, and CON(R)2, wherein R is H, (C1-C6)-alkyl, phenyl, or (C1-C6)-alkylphenyl;
• and
• (b) reacting the reaction mixture containing the ketodiazophosphonate compound of Formula II with cyclopropanecarboxaldehyde using a second non-nucleophilic base and a protic solvent to yield the cyclopropaneacetylene.