Preparation of 3-arylmethylindoles as selective COX-2 inhibitors

The 3-arylmethylation of indoles using TMSOTf/Et3SiH with a wide variety of substituted benzaldehydes has been accomplished. Under these mild Lewis acid mediated reductive conditions, it was demonstrated that indoles bearing both 6-MeSO2, and 2-methyl substituents could be 3-arylmethylated in good to excellent yields to afford the corresponding 3-arylmethyl indoles, effective as selective COX-2 inhibitors. I it addition, the viability of this method for the reductive alkylation of indoles by ketones was demonstrated and shown to be C-3 regioselective. For indoles bearing both a 6-MeSO2, and 2-cyano substituent where this indole reductive alkylation methodology was unsuccessful, all unprecedented Pd(0) mediated arylorganozinc Coupling With the requisite Substituted 3-methylcarbonatomethylindole proved Successful in affording the desired 2-cyano-6-MeSO2-3-arylmethylindoles effective as selective COX-2 inhibitors. (C) 2004 Elsevier Ltd. All rights reserved.