Abstract The synthesis of new difunctionalized 2,6-dioxatricyclo[188.8.131.52 3,7]nonanes is described. This type of structure is an interesting synthetic building block for potential bioactive molecules and it was prepared from 8-oxabicyclo[3.2.1]oct-6-en-3-one having a NHBoc function on C-1. This precursor was obtained by a [4+3] cycloaddition reaction of 2- tert-butoxycarbonylaminofuran and the oxyallyl cation generated in situ from 2,4-dibromo-3-pentanone. Reduction of the carbonyl group at C-3 was accomplished in high yield and stereoselective manner to afford the corresponding axial alcohol at C-3 as a major product. Further intramolecular haloetherification of this type of alcohols with NBS and I(py)2BF 4 led to the corresponding bromo and iodo-derivatives at C-8 of the 2,6-dioxatricyclo[184.108.40.206 3,7]nonane framework, in high yield. Epoxidation of 8-oxabicyclo[3.2.1]oct-6-en-3-ol followed by treatment with NaCN, NaN 3, and/or NaOH in MeOH afforded 8-hydroxy-2,6-dioxatricyclo[220.127.116.11 3,7]nonanes in high yield via a transannular hydroxycyclization mediated by a base and through an alkoxide intermediate. The new 2,6-dioxatricyclo[18.104.22.168 3,7]nonanes were tested for biological activity against HIV-1 virus and MT-4 lymphoid cell line, showing a low anti-HIV activity and a high degree of cytotoxicity.