In a previous communication, the reaction of some 3,4-dichlorocoumarins with phenylmagnesium bromide to fqm 3-chloroflavones was announced (3). In this article these reactions are described in more detail as well as the use of such a condensation in a sequence of reactions to form a benzofurobenzopyranone. The 3,4-dichlorocoumarins (4) (I), were converted into the 3-chloroflavones (II) in good yields by treat- ment with phenylmagnesium bromide in benzene-ether ...
