Synthesis of spiro-1,2-dihydropyridine derivatives via cycloisomerization of 3-aza-1,5-enynes catalyzed by gold(I) complex/polyoxometalate hybrids.

This study reports an optimized method for the synthesis of spiro-1,2-dihydropyridines via the cycloisomerization of 3-aza-1,5-enynes, catalyzed by heterogeneous gold(I)-polyoxometalate (POM) hybrids. By replacing traditional homogeneous catalysts with these hybrid systems, we achieved high yields (up to 82% isolated) in short reaction times, while minimizing product degradation. The reaction scope was demonstrated across a broad range of substrates, including aryl, alkyl, and heterocyclic derivatives, as well as variations in ring size and nitrogen substituents using 5 mol % of [AuI(IPr)(MeCN)][H5P2W18O64] as catalyst.