Flexible Tetrahydropyran Synthesis from Homopropargylic Alcohols Using Sequential Pd–Au Catalysis

A flexible synthetic method toward highly substituted tetrahydropyran is reported. The key transformation involves atom-efficient sequential metal catalysis consisting of Pd-catalyzed addition of homopropargylic alcohols to alkoxyallene and the subsequent gold­(I)-catalyzed cycloisomerization. Notably, this method gives access to both 2,6-<i>cis</i>- and 2,6-<i>trans</i>-tetrahydropyrans possessing diverse substitution patterns