Iridium-Catalyzed Triborylation of 3-Substituted Indoles
Andrew S. Eastabrook A and Jonathan Sperry A B
+ Author Affiliations
- Author Affiliations
A School of Chemical Sciences, University of Auckland, 23 Symonds Street, Auckland 1142, New Zealand.
B Corresponding author. Email: j.sperry@auckland.ac.nz
Australian Journal of Chemistry 68(12) 1810-1814 https://doi.org/10.1071/CH15393
Submitted: 1 July 2015 Accepted: 29 July 2015 Published: 27 August 2015
Abstract
Readily available 3-substituted indoles undergo a one-pot iridium-catalyzed triborylation at the C2, C5, and C7 sites. 1H NMR analysis indicates borylation at C2 and C7 occurs first (no monoborylated product is observed), with the third borylation occurring as a separate, distinct step that is sterically directed to C5 by a combination of the substituent at C3 and the boronate at C7. The resulting tetrasubstituted indoles possess a substitution pattern that is cumbersome to prepare using existing methods.
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