Preparation and reactions of 1-(tert-butyldimethylsilyl)-3-lithioindole: Regioselective synthesis of 3-substituted indoles

Halogen-metal exchange from the corresponding 3-bromoderivative yields 1-(tert-butyldimethylsilyl)-3-lithioindole which reacts with electrophiles to form 3-substituted indoles. The N-silyl-3-lithioindole is of value in the synthesis of 3-substituted indoles due to the absence of ring fragmentation and rearrangement and the easy elimination of the protecting group.