Synthesis of bicyclic diones and thiones. Facile methylation of the enolates of bicyclo[2.2.1]heptane-2,5-dione and bicyclo[2.2.2]octane-2,5-dione. An AM1 computational study of bicyclic enolates

A group of bicyclic ketones and thiones have been synthesized for homenolization studies. Bicyclo[2.2.1]heptane-2,5-dione (6) undergoes unusually rapid tetramethylation giving 3,3,6,6-tetramethylbicyclo[2.2.1]heptane-2,5-dione (1) in good yield. Treatment of 1 with P 2 S 5 in xylene gave 3,3,6,6-tetramethylbicyclo[2.2.1]heptane-2,5-dithione (2) and 3,3,6,6-tetramethyl 15-oxo-bicyclo[2.2.1]heptane-2-thione (3), which was converted into 4 with …