The synthesis of bicyclo[2.2.1]heptanes with useful functionality at each bridgehead is achieved by radical cyclization of appropriately substituted 4-methylene- and 4-benzyloxyimino- cyclohexylmethyl radicals. The latter process, for example, leads to a bridgehead amine. Optimum yields are achieved when the reactions are conducted at 110� with slow addition of tributyltin hydride; under these conditions, the uncyclized isomer is either not detected, or formed in very small quantity. Production of a mixture of five- and six-membered cycloalkanones from similar treatment of the analogous 4-oxocyclohexylmethyl radicals reveals that the reaction is medicated by the corresponding 1-norbornyloxy radical.
通过对适当取代的 4-亚甲基和 4-苄氧基亚氨基环己基甲基进行自由基环化,可以合成在每个桥头都具有有用官能团的双环[2.2.1]庚烷。例如,后一过程会产生桥头胺。当反应在 110� 温度下进行并缓慢加入氢化三丁基锡时,可获得最佳产率;在这些条件下,未环化的异构体要么检测不到,要么形成的数量极少。通过对类似的 4-oxocyclohexylmethyl 自由基进行类似处理,生成五元和六元环烷酮混合物,结果表明该反应受相应的 1-正硼氧基自由基的影响。