ORGANIC
LETTERS
2003
Vol. 5, No. 22
4129-4131
Synthesis of Diprotected
Monosubstituted Hydrazine Derivatives
from tert-Butyl Carbazates and Boronic
Acids
George W. Kabalka* and Sankar K. Guchhait
Departments of Chemistry and Radiology, The UniVersity of Tennessee,
KnoxVille, Tennessee 37996
Received August 14, 2003
ABSTRACT
Diprotected monosubstituted hydrazine derivatives have been prepared via the reaction of tert-butyl carbazates with boronic acids catalyzed
by cuprous chloride at room temperature.
Diprotected monosubstituted hydrazine derivatives are ver-
satile intermediates in the synthesis of aromatic amines,1 aryl
hydrazines,2 substituted hydrazine derivatives,3 azatides,4 and
â-strand mimics.5 These products are used in the preparation
of a wide variety of biologically and industrially valuable
compounds.3a,f,g,6 Monosubstituted hydrazines are also in-
termediates in the preparation of heterocyclic compounds
such as pyrazoles,7a indazoles,7b imidazolinones,7c and
cinnolines.7d 2-Heteroaryl hydrazines8 are interesting syn-
thetic targets due to their efficiency as ligands for a variety
of metal complexes.9 Boc- or trichloroethoxycarbonyl (Troc)-
protected aryl hydrazines are generally prepared by electro-
philic amination1,7b,10 of electron-rich arenes utilizing dialkyl
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* To whom correspondence should be addressed. Phone: (865) 974-
3260. Fax: (865) 974-2997.
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10.1021/ol035544v CCC: $25.00 © 2003 American Chemical Society
Published on Web 10/09/2003