Organic & Biomolecular Chemistry
Communication
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Fig. 2 Plausible catalytic cycle.
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Pd-carbene B. Then nucleophilic addition of amine affords C
and regenerates PdL2 to the next catalytic cycle. Secondly, C is
activated by PdL2 and release of HL generates intermediate E,
which undergoes β-H elimination to afford dienone F as well
as another HL and Pd(0) species. Finally, F would quickly tau-
tomerize to its more stable isomer G and the Pd(0) species
could be reoxidized to Pd(II) by O2 and HL to complete the
second catalytic cycle.
In summary, we have developed a new strategy for accessing
2-amino-phenols. This approach includes Pd-catalyzed NHI
and a tandem oxidative dehydrogenation/aromatization under
an air atmosphere. In addition, this method allows straight-
forward access to the key precursors for synthesizing 1-oxyge-
nated carbazoles, as well as an efficient way to prepare
2-alkylamino-phenols from non-aromatic substrates. Further-
more, this newly established methodology was expanded to
the synthesis of murrayafoline A on a gram scale.
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We gratefully acknowledge the National Natural Science
Foundation of China (21172023), a project funded by the
Priority Academic Program Development of Jiangsu Higher
Education Institutions (PAPD) and the Science & Technology
Agency of Jiangsu Province (BY2012096) for their financial
support.
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Notes and references
1 For reviews, see: (a) H.-J. Knölker and K. R. Reddy, Chem.
Rev., 2002, 102, 4303; (b) A. W. Schmidt, K. R. Reddy and 12 For Pd-catalyzed enantioselective N–H insertion, see:
H.-J. Knölker, Chem. Rev., 2012, 112, 3193 and reference
cited therein.
(a) Y. Zhu, X. Liu, S. Dong, Y. Zhou, W. Li, L. Lin and
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Org. Biomol. Chem., 2014, 12, 4084–4088 | 4087