Bl. Flynn et al., A novel palladium-mediated coupling approach to 2,3-disubstituted benzo[b]thiophenes and its application to the synthesis of tubulin binding agents, ORG LETT, 3(5), 2001, pp. 651-654
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Flexible, convergent access to 2,3-disubstituted benzo[b]thiophenes has bee
n developed. The most concise approach involves sequential coupling of o-br
omoiodobenzenes with benzylmercaptan and zinc acetylides to give benzyl o-e
thynylphenyl sulfides which react with iodine to give 3-iodobenzo[b]thiophe
nes in a 5-endo-dig iodocyclization. These iodides can be further elaborate
d using palladium-mediated coupling and/or metalation techniques. This meth
od has been applied to the synthesis of some novel tubulin binding agents.