Stereoselective Synthesis of Hexahydro-1H-spiro[isoquinoline-4,4′-pyran] Scaffolds through an Intramolecular Prins Cascade Process

A novel tandem cyclization strategy has been developed for the synthesis of hexahydro-1H-spiro[isoquinoline-4,4′-pyran] derivatives through the condensation of 3-((benzylamino)methyl)but-3-en-1-ol with aldehydes using BF3·OEt2. The reaction proceeds in a highly stereoselective manner, leading to a single diastereoisomer. This approach is a simple and efficient alternative for the synthesis of pharmacologically important spiroisoquinoline scaffolds.