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Published on: May 26, 2019
Pd-Catalyzed Chemoselective O‑Benzylation of Ambident 2‑Quinolinone Nucleophiles
Melissa Cadena1, Roberto Silva Villatoro1, Jyoti Shah Gupta1
1The Max and Minnie Tomerlin Voelcker Laboratory for Organic Chemistry, Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States.
Abstract:
We have discovered and developed a highly chemoselective O-benzylation of ambident 2-quinolinone nucleophiles via Pd-catalysis. Detailed reaction analysis using direct-injection high resolution mass spectrometry (DI-HRMS) combined with in situ 31P NMR implicate a phosphine mono-oxide Pd(II) η 1-benzyl complex as a key intermediate on the catalytic cycle. Extrapolation of this method to selectively O-alkylate a series of substituted 2-quinolinones using several benzylic electrophiles is demonstrated providing 2-benzyloxy quinolines in good yields and high O:N selectivities (up to 100:1) utilizing as little as 1 mol % Pd-catalyst to achieve these results.
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