Indium-Catalyzed Synthesis of Furans and Pyrroles via Cyclization of α-Propargyl-β-keto Esters
Hayato Tsuji, Ken-ichi Yamagata, Yasuyuki Ueda, Eiichi Nakamura*
*Department of Chemistry, School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, Email: nakamurachem.s.u-tokyo.ac.jp
H. Tsuhi, K.-i. Yamagata, Y. Ueda, E. Nakamura, Synlett, 2011, 1015-1017.
DOI: 10.1055/s-0030-1259930 (free Supporting Information)
In(OTf)3 or In(NTf2)3 effectively catalyze the cycloisomerization reaction of α-propargyl-β-keto esters and their imine analogues to afford trisubstituted furans and pyrroles, respectively. Both terminal and internal alkynes take part in the reaction with good functional-group compatibility in the presence of only a small catalyst loading.
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