ORGANIC
LETTERS
2011
Vol. 13, No. 23
6152–6155
Direct Condensation of Sulfonamide and
Formamide: NaI-Catalyzed Synthesis of
N-Sulfonyl Formamidine Using TBHP as
Oxidant
Shulin Chen,† Yuan Xu,† and Xiaobing Wan*,†,‡
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry,
Chemical Engineering and Materials Science, Soochow University, Suzhou 215123,
P. R. China, and State Key Laboratory of Applied Organic Chemistry, Lanzhou
University, Lanzhou 730000, P. R. China
Received September 10, 2011
ABSTRACT
A new N-sulfonyl formamidine synthesis was developed via NaI-catalyzed direct condensation of sulfonamide and formamide. The green
methodology is featured by high atom economy, easily available starting materials, the lack of need for a transition-metal catalyst, no requirement
of hazardous reagent, operational simplicity, and good tolerance with diverse functional groups. Mechanistic studies suggest that the protocol
proceeds based upon in situ generated TsN NaI.
3
N-Sulfonylamidines are unique structural motifs in many
bioactive natural products and pharmacophores,1 and
they also serve as useful synthetic intermediates2 (Figure 1)
and efficient coordinating ligands.3 Conventional methods
known for making N-sulfonylamidines involve harsh con-
ditions and corrosive and/or specially designed reagents.4
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‡ Lanzhou University.
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10.1021/ol2024604
Published on Web 10/31/2011
2011 American Chemical Society