A short synthesis of the endogenous plant metabolite 7-hydroxyoxindole-3-acetic acid (7-OH-OxIAA) using simultaneous C-H borylations

作者：Homer Joshua A; Sperry Jonathan^*

来源：Tetrahedron Letters, 2014, 55(42): 5798-5800.

DOI：10.1016/j.tetlet.2014.08.104

• 7-Hydroxyoxindole-3-acetic acid
• 7-OH-OxIAA
• Auxin
• Borylation
• C-H functionalisation

Methyl indole-3-acetate undergoes two simultaneous iridium-catalysed borylations to deliver exclusively 2,7-diboronate, with the ligand 3,4,7,8-tetramethyl-1,10-phenanthroline (Me(4)Phen) pivotal in driving the diborylation to completion. Subsequent oxidation-hydrolysis of the diboronate provides methyl 7-hydroxyoxindole-3-acetate which upon hydrolysis of the ester delivers 7-OH-OxIAA, an antioxidant, endogenous metabolite of indole-3-acetic acid found in various types of corn. This route has an overall yield of 50%, involves a single chromatographic purification and is an efficient alternative to existing syntheses, made possible by executing simultaneous oxidations at the indole C2 and C7 sites.

• 出版日期2014-10-15