PREPARATION OF ORGANOSTANNANES BY INTERMOLECULAR RADICAL SUBSTITUTION-REACTIONS

A new approach to the synthesis of aromatic stannanes via novel radica l substitution reaction of aromatic sulfones is presented. Thus, alpha -heterocyclic aromatic sulphones derived from indole, pyrrole, pyrazol e, furans and thiophenes undergo rapid and high yielding ipso-substitu tion to furnish organostannanes. This methodology has been extended to beta-heterocyclic aromatic sulfones derived from indoline and dibenzo furan, The methodology has some limitations as shown in the lack of re activity of 3-phenylsulfonyl indole derivative 17 and some phenylthio- substituted heteroaromatic systems 22-24. Phenylsulfinyl substituted i ndoles can also undergo the desired substitution reaction ss shown in the successful transformation of 25 to the corresponding stannane 4a. Copyright (C) 1996 Elsevier Science Ltd