Gold(I) catalysed cycloisomerisation of β-hydroxy propargylic esters to dihydropyrans/2H-pyrans via allene intermediates

Efficient cycloisomerisation of β-hydroxy propargylic esters to dihydropyrans/2H-pyrans via 1,3-carboxylate migration followed by regioselective hydroxyl addition to the transient allene intermediate catalysed by Ph3PAuCl/AgSbF6 is presented. Similar reactions on phosphorylated precursors led to phosphono-furans and phosphono-pyrans. In a few cases, self-condensation of β-hydroxy propargylic esters via catalytic nucleophilic substitution to macrocycles is observed. Key products are characterised by X-ray structure determination.