Synthesen von Tricyclo [5.2.1.0 4,8 ]decan (2‐Homobrendan)

Syntheses of Tricyclo [5.2.1.0 4,8 ]decane (2‐Homobrendane) Three different approaches to tricyclo [5.2.1.0 4,8 ] decane (5) (and derivatives thereof), one of the 19 isomeric hydrocarbons of the ‘adamantaneland’, are described: (1) Cyclization of properly functionalized bicyclo [3.2.1]octanes as 32 (cyclialkylation), 40+42 (thermocyclization) and 44+45 (photocyclization); (2) Silver‐(I)‐ion catalyzed rearrangement of 5,7‐ and 5,10‐Dehydroprotoadamantane ( 63 and 64 , respectively) yielding tricyclo[5.2.1.0 4,8 ]dec‐2‐ (39) and ‐5‐ene (59) , respectively; (3) Thermal eliminative rearrangement of the 10 endo‐p ‐toluenesulfonate and ‐methanesulfonate of protoadamantane ( 71 and 72 ) and protoadamant‐4‐ene ( 76 and 77 ), respectively, yielding tricyclo [5.2.1.0 4,8 ]dec‐2‐ene (39) and ‐2, 5‐diene (15) , respectively.