Hydroxyhopanone (1) was converted via two alternative routes (1→ 9→ 11a→ 12→ 14→ 15→ 16 and 1→ 10→ 17→ 18→ 19→ 20) to A-neohop-21-ene (16) and A-neohop-3-ene (20), respectively. These unsaturated hydrocarbons (16 and 20) were found to be identical; this provided evidence to confirm the 21β-H configuration for 1.
