Acetylenes from Aldehydes. Preparation of Ethynylphenols and Phenylacetylenes by Flash Vacuum Pyrolysis of Isoxazolones*

The flash vacuum pyrolysis method of synthesis of acetylenes from aldehydes via isoxazolones is a convenient method for the preparation of a variety of derivatives, including kinetically unstable, sensitive compounds such as the ethynylphenols.