Efficient, highly diastereoselective MS 4 Å-promoted one-pot, three-component synthesis of 2,6-disubstituted-4-tosyloxytetrahydropyrans via Prins cyclization

• Naseem Ahmed and
• Naveen Kumar Konduru

Beilstein J. Org. Chem. 2012, 8, 177–185, doi:10.3762/bjoc.8.19

• -hydroxytetrahydropyran in excellent yields (95–96%). Keywords: aromatic homoallylic alcohols; 2,6-disubstituted-4-tosyloxytetrahydropyrans; MS 4 Å; Prins cyclization; PTSA; Introduction Substituted tetrahydropyrans are common structural motifs in numerous biological molecules and natural products that include

• tetrahydropyrans [30]; however, this method is restricted to electron withdrawing groups containing aromatic homoallylic alcohols. Similarly, She et al. recently have reported a new approach for the synthesis of 2,4,6-trisubstituted tetrahydropyrans via a Prins cyclization [31]. With this method, both symmetrical

• ). Further, cleavage of the 4-tosyl group under mild conditions afforded 4-hydroxytetrahydropyran in excellent yields (95–96%). Results and Discussion The starting materials, aromatic homoallylic alcohols, were readily prepared by treatment of aromatic aldehydes with allylic Grignard reagents under a