A study involving the preparation and thermolysis of substituted 6-exo-(1-alkenyl)bicyclo[3.1.0]hex-2-ene systems (14, 15, 23, 29, 40) shows (a) that C-8 functionalized bicyclo[3.2.1]octa-2,6-dienes can be prepared readily via this methodology (14 → 16; 15 → 17), (b) that the rearrangement reaction is stereospecific even when the 6-(1-alkenyl) group is substituted with a sterically bulky isopropyl group (23 → 24; 29 → 30), and (c) that the method can be extended to include the preparation of tricyclic systems (40 → 41).