Abstract: A short, general approach for the synthesis of angular triquinanes is delineated. The key element of this approach is the carbonium-ion-mediated transannulation in the bicyclo [6.3. 0] undecane system. New syntheses of appropriately functionalized bicyclo [6.3. 0] undecanes 1 la and 1 lb from cheap, abundantly available 1, 5-~ yclooctadiene have been developed. These have been cyclized in formic acid and elaborated to tricycl0 [6.3. ...