First synthesis of cis-enediynes from 1,5-diynes by an acid-mediated allylic rearrangement
The first synthesis of cis-enediynes 11 from 1,5-diyne 7 is achieved by treatment with 1 equivalent of CSA in CH2Cl2 at 20°C in the presence of ROH or RSH to provide 11 as the major products in good yield. An 11-membered ring enediyne 15 was prepared similarly in 47% yield.