Synfacts 2014; 10(8): 0846
DOI: 10.1055/s-0034-1378419
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Silver-Catalyzed [3+2] Cyclization of α-Imino Esters with Isocyanoacetate

Hisashi Yamamoto
Biplab Maji
Shao P.-L, Liao J.-Y, Ho YA, Zhao Y * National University of Singapore, Singapore
Highly Diastereo- and Enantioselective Silver-Catalyzed Double [3+2] Cyclization of α-Imino Esters with Isocyanoacetate.

Angew. Chem. Int. Ed. 2014;
53: 5435-5439
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18. Juli 2014 (online)



The authors present a double [3+2] cyclization of α-amino esters with isocyanates to produce highly functionalized oxazole-imidazoles. Therefore, a silver oxide quinine derived amino phosphine ligand was used. For the pioneering work regarding isocyanates using a gold catalyst, see: Y. Ito, M. Sawamura, T. Hayashi J. Am. Chem. Soc. 1986, 108, 6405–6406.



Kinetic studies identified two cyclization processes to be step-wise. The intermediates, mono-[3+2] cyclization products, were isolated. The products can be hydrolyzed to yield functionalized α,β-diamino esters.