Reagent-controlled regioselective [3,3]-sigmatropic rearrangement of N-trifluoroacetyl enehydroxylamine and its synthetic application

摘要

Regioselective [3,3]-sigmatropic rearrangement provides a novel method for the construction of hexahydrodibenzofuran with a quaternary carbon in the ring juncture. Upon treatment with TFAA. oxime ethers carrying an electron-withdrawing group smoothly underwent regioselective rearrangement to give the hexahydrodibenzofuran with a quaternary carbon. On the other hand, the reaction of oxime ethers with TFAT-DMAP gave tetrahydrodibenzofurans carrying a substituent at the 4-position. The hexahydrodibenzofuran with a quaternary carbon was effectively converted into a key intermediate for lunarine synthesis.