Synlett 2010(6): 889-892  
DOI: 10.1055/s-0029-1219538
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Enantioselective Diels-Alder Cycloadditions with β-Substituted Pyrazolidinone Propiolimides

Mukund P. Sibi*, Wilfredo Cruz Jr., Levi M. Stanley
Department of Chemistry and Molecular Biology, North Dakota State University, Fargo, ND 58105, USA
Fax: +1(701)2311057; e-Mail: Mukund.Sibi@ndsu.edu;
Further Information

Publication History

Received 11 November 2009
Publication Date:
18 February 2010 (online)

Abstract

Chiral Lewis acid catalyzed Diels-Alder cycloadditions between β-substituted pyrazolidinone propiolimides and cyclic dienes have been studied. A catalyst prepared from Sc(OTf)3 and ­t-Bu-pybox ligand promotes the formation of enantioenriched diene cycloadducts in moderate to high yield and good enantioselectivity from the reactions of acetylenic dienophiles and cyclic dienes.

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10

All products were isolated as pure compounds after column chromatography and characterized by spectroscopic and other analytical techniques.