Meyer-Schuster rearrangement of propargylic alcohols mediated by phosphorus-containing Brønsted acid catalysts.

Commercially available (aqueous) hypophosphorus acid is an efficient catalyst for the synthesis of α,β-unsaturated carbonyl compounds from their corresponding propargylic alcohols. Reactions were carried out in technical toluene in the presence of air and in several instances the desired products were isolated analytically pure after a simple work-up.