The thermolysis of aryl desyl ethers. Formation of furan derivatives

Thermal reactions of aryl desyl ethers PhCOCH(OAr)Ph (Ar = Ph, p-tolyl) 1, 2 gave 2,3-diphenylbenzo[b]furan 5a,b and phenols as major products in addi tion to small amounts of toluene, benzil, benzoic acid, benzophenone, arylb enzoate, p-benzylphenol, 2,3,4,5-tetraphenylfuran 4 and 2,3-diphenylbenzo[1 ,4] dioxin 6a,b. In the presence of isoquinoline as a radical trap, 1 gave 1-phenylisoquinoline beside the previous products. Analogous results, in ad dition to diphenylmethane and benzophenone as major products as well as 1,1 ,2,2-tetraphenyl ethane and dibenzhydryl ether as minor products, were also obtained on heating the benzhydryl desyl ether 3. A free radical mechanism has been postulated to take place through the initial homolysis of the C-O Ar bond to account for the identified products.