A general synthetic route to dibenzospiropyrans and dinaphthospiropyrans from dibenzofuran and dinaphthofuran

摘要

The reaction of dibenzofuran or dinaphthofuran with lithium in anhydrous diethyl ether led to a solution of the corresponding C,O-dilithiated intermediate which, upon treatment with 1, 3,3-trimethylindolin-2-one or different coumarin derivatives at -78 degrees C, afforded, after hydrolysis, dibenzospiropyrans and dinaphthospiropyrans in good yields. The structures of all new compounds were determined by single crystal X-ray analysis.