Microwave-Assisted Cyclization under Mildly Basic Conditions: Synthesis of 6H-Benzo[c]chromen-6-ones and Their 7,8,9,10-Tetrahydro Analogues

Aryl 2-bromobenzoates and aryl 2-bromocyclohex-1-enecarboxylates are cyclized by microwave irradiation in dimethylformamide in the presence of K 2 CO 3 to give the corresponding 6 H -benzo[ c ]chromen-6-ones and their 7,8,9,10-tetrahydro analogues, respectively, in 50–72% yields. Aryl 3-bromoacrylates are also converted into 2 H -chromen-2-ones under the employed conditions.