Abstract A convenient synthesis of the strained methylene-bridged trans-cyclooctenes bicyclo [3.3. 1]-1 (2)-nonene (1), bicyclo [4.2. 1]-1 (8)-nonene (2), and bicyclo [4.2. 1]-1 (2)- nonene (3) by the intramolecular Wittig reaction is described (see Schemes 1–4). The (3- oxocycloalkyl) alkyl-phosphonium bromides 20, 27 and 38 undergoing cyclization to the bridgehead olefins are formed by simple reaction sequences. The spectral properties (IR., ...
![Bicyclo[4.2.1]non-1(2)-ene结构式](https://image.chemsrc.com/caspic/171/23057-36-5.png)