Dihetero-isotwistanes

The first synthesis of a tricyclo[4.3.1.0 ]decane, namely of pure carbocyclic iso-twistane [G 2 X(2) = CHj, Y(7) = CHj ], was reported by Vogt S in 1968. Almost at the same time 2,7-dihetero-isotwistanes (G 2) and/or derivatives thereof became available. Today a variety of such compounds are known  

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Restriction among the great number of possible dihetero-tricyclodecanes to such with a carbocyclic 8-membered ring (cyclooctane) as basic skeleton, which is crosswise bridged by two heteroatoms, and restriction to 5-, 6- and 7-membered heterocyclic rings, isomeric dihetero-tricyclodecanes of the following five different stmctural types are possible 2,6-dihetero-adamantane (G 7 ) 2,7-dihetero-isotwistane (G 2,7-dihetero-twistane (G S) 2,8-dihetero-homotwistbrendane (G 4) and 2,6-dihetero-tricyclo[3.3.2.0 Jdecane (G 5) . 

Syntheses of various 2,7-dihetero-isotwistanes by bridging suitable bicyclononanes were successful applying one or several of the pathways F-M. Ring closures occurred either by nucleophilic attack at a double bond (in G 15, G 16 and G 7 7), at a carbonyl carbon (in G 20) and at an epoxide ring (in G 21 and G 22) or by substitution of a leaving group (in G 75 and G 79). 

Starting Material 2,7-Dihetero-isotwistanes and -twistanes as Well as... 

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