Directed C-7 lithiation of 1-(2,2-diethylbutanoyl)indoles

Article abstract of DOI:10.1016/S0040-4020(99)00487-1

Directed lithiation of 1-acylindole derivatives was investigated. It was discovered that a bulky 2,2-diethylbutanoyl (DEB) group could promote unusual C-7 lithiation. Especially in the case of 3-substituted 1-(DEB)indoles, selective C-7 lithiation was achieved in a synthetically useful level. The DEB group was readily removed by H₂O/tert-BuOK/THF system after functionalization at C-7. This, therefore, allows easy generation of 3,7- disubstituted indole derivatives which are not readily available by conventional methodologies.