jo300330u_si_001.pdf (1.72 MB)
Iridium-Catalyzed C–H Borylation-Based Synthesis of Natural Indolequinones
journal contribution
posted on 2012-03-16, 00:00 authored by Christy Wang, Jonathan SperryAn iridium-catalyzed C–H borylation provides the
key step
in a short synthesis of two indolequinone natural products. This regioselective
C–H functionalization strategy delivers 7-borylindoles that
undergo facile oxidation–hydrolysis to 7-hydroxyindoles and
subsequent oxidation to the desired indolequinones, thereby demonstrating
a powerful application of the iridium-catalyzed C–H borylation
reaction. A significant result has arisen from the iridium-catalyzed
borylation of N-diethylhydrosilyl-6-methoxyindole;
even in the presence of a substituent at C6, the N-hydrosilyl group still directs borylation exclusively into the more
sterically hindered C7 position in preference to C2.