Rates of reductive elimination of substituted nitrophenols from the (indol-3-yl)methyl position of indolequinones

Journal article

A series of indolequinones bearing substituted nitrophenols on the (indol-3-yl)methyl position was synthesised. The nitrophenol leaving groups were appropriately substituted to give a wide range (4 units) in phenolic pKa value. The rate of reductive elimination of phenoxide anions from the (indol-3-yl)methyl position of semiquinone radicals was dependent upon this pKa, with a decrease in 3.8 pK units shortening the half-life from 28 to 1.5 ms. Only 2,4-dinitrophenol (pKa = 3.9) was eliminated from an unsubstituted (indol-3-yl)methyl position at a rate that would compete with reoxidation of the radical by oxygen. A nitrothiophenol leaving group was eliminated comparatively slowly and only from the hydroquinone. These studies demonstrate the dependence upon leaving group pKa of the rate of reductive elimination from the (indol-3-yl)methyl position of indolequinones.

Authors: Swann, E; Moody, C; Stratford, M; Patel, K; Naylor, M

• Publication status: Published
• Journal: JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
• Issue: 8
• Pages: 1340-1345
• Publication date: 2001-01-01
• DOI: 10.1039/b101842f
• EISSN: 1364-5471
• ISSN: 1472-779X
• Language: English