THE THERMOLYSIS OF ARYL DESYL ETHERS - FORMATION OF FURAN-DERIVATIVES

Thermal reactions of aryl desyl ethers PhCOCH(OAr)Ph (Ar = Ph, p-tolyl ) I and II: gave 2,2-diphenylbenzo[b]furan 1a,b and phenols 2 and 3 as major products, in addition to small amounts of toluene 4, benzil 5, benzoic acid 6, benzophenone 7, aryl benzoate 8 and 9, p-benzylphenol 10, 2,3,4,5-tetraphenylfuran 11 and 2,3-diphenylbenzo[1,4]dioxin 12a,b . In the presence of isoquinoline as a radical trap, I gave 1-phenylis oquinoline 13 as well as the previous products. Analogously, in additi on to diphenylmethane 14 and benzophenone 7 as major products, 1,1,2,2 -tetraphenylethane 15 and dibenzhydryl ether 16 as minor products were obtained on heating the benzhydryl desyl ether III. A free radical me chanism has been postulated to take place through the initial homolysi s of the C-OAr bond to account for the identified products. (C) 1998 E lsevier Science B.V. All rights reserved.