Directed lithiation of 1-(triisopropylsilyl)gramines 1 with tert-butyllithium followed by reaction with trimethylsilylmethyl azide produced 4-amino-1-(triisopropylsilyl)gramines 7. The N-tert-butoxycarbonyl derivatives 8 were lithiated selectively at C-5 with tert-butyllithium and the lithiated species were reacted with a variety of electrophiles to give 5-functionalized compounds, 9 and 10. A facile method to produce 3,4,5-trisubstituted indoles from readily available gramine derivatives is thereby established. © 2005 Elsevier Ltd. All rights reserved.
Fukuda, T., Akashima, H., & Iwao, M. (2005). Synthesis of 3,4,5-trisubstituted indoles via iterative directed lithiation of 1-(triisopropylsilyl)gramines. Tetrahedron, 61(28), 6886–6891. https://doi.org/10.1016/j.tet.2005.04.064