The Structures of Two Major Intermediates in Trifluoromethanesulfonic Acid-Catalyzed Rearrangement of Tricyclo[5.2.2.02,6]undecane

Two major intermediates of unknown structure (unknown E and D) found in trifluoromethanesulfonic acid-catalyzed rearrangement of tricyclo[5.2.2.02,6]undecane (1) to 4-homoisotwistane (4) were identified as tricyclo[5.4.0.04,8]undecane (2) and tricyclo[5.3.1.04,11]undecane (3), respectively, by independent syntheses.