Regioselective lithiation and substitution of tricarbonyl-(η6-1-methylindole)-chromium(0) : X-ray crystal structure analysis of tricarbonyl-(η6-1-methyl-2-trimethylsilyl-7-ethoxycarbonyl-indole)chromium(0)

Abstract

Tricarbonyl(η⁶-1-methylindole)chromium(0) is lithiated by n-butyl-lithium at C-2 whereas tricarbonyl-(η⁶-1-methyl-2-trimethylsilylindole)chormium(0) is lithiated predomiantly at C-7, as shown by X-ray analysis of the derived 7-ethoxycarbonyl derivative, and the 7-lithio species is substituted in good yield by a range of electrophiles.