SYNTHESIS OF A 2,7-DIOXATRICYCLO[4.2.1.0(3,8)]NONANE - A MODEL STUDY FOR POSSIBLE APPLICATION IN A SYNTHESIS OF DICTYOXETANE

A method for the synthesis of the 2,7-dioxatricyclo[4.2.1.0(3,8)]nonan e ring system characteristic of the marine diterpene dictyoxetane has been developed. This method utilizes a dipolar cycloaddition of a 3-ox idopyrylium salt to create the carbon skeleton (Scheme 1) and employs an intramolecular S(N)2 displacement to form the oxetane ring (Schemes 9, 10, 13). The route described could easily be adapted to incorporat e additional functionality, making it potentially useful in a total sy nthesis of dictyoxetane.