Oxidative biaryl coupling reaction of phenol ether derivatives using a hypervalent iodine(III) reagent

The hypervalent iodine(III)-induced intramolecular biaryl coupling reaction of phenol ether derivatives (nonphenolic derivatives) was investigated with the aim of preparing various dibenzo heterocyclic compounds. 1,3-Diarylpropanes (1a-e), N-benzyl-N-phenethylamines (2a-c) and N,N-dibenzylamines (3a-e) react with a hypervalent iodine reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA), containing BF3. Et2O in CH2Cl2 to give the biaryl coupling products (4-6) in good yield. As an application of the reaction, we examined the synthesis of oxygen- and sulfur-containing dibenzoheterocyclic compounds (12-15), whose side chain moiety could be easily cleaved by the known method to give 2,2'-substituted biphenyl compounds (16-18).