Indium-mediated synthesis of 2,6-disubstituted tetrahydropyrans in aqueous media

ORGN 107

Thomas G. Minehan, thomas.minehan@csun.edu, Minh Pham, and Amir Allatabakhsh. Department of Chemistry and Biochemistry, California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330
In the presence of indium metal, 3-iodo-2-[(trimethylsilyl)methyl]propene reacts with sequentially added aldehydes in aqueous media to provide cis-2,6-disubstituted tetrahydropyrans in good yields. It is likely that Lewis-acidic indium salts formed upon allylation of the first equivalent of aldehyde promote a silyl-Prins type reaction with the second equivalent of added aldehyde. The diastereoselective synthesis of cyclopentenyl and cyclohexenyl-fused pyrans via this one-pot, three-component process will also be presented.