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Synfacts 2010(11): 1230-1230  
DOI: 10.1055/s-0030-1258756
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart ˙ New York

Gold(I)-Catalyzed Synthesis of Furo[3,4-d]-[1,2]oxazines

Contributor(s): Victor Snieckus, Emilie David
F. Liu, D. Qian, L. Li, X. Zhao, J. Zhang*
East China Normal University, Shanghai and Shanghai Institute of Organic Chemistry, P. R. of China
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Publication History

Publication Date:
21 October 2010 (online)

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Significance

A previous regio- and diastereo­selective tandem cyclization-[3+3] cycloaddition of 2-(1-allynyl)-2-alken-1-ones 1 with nitrones 2 lead to furo[3,4-d][1,2]oxazines 3 with moderate enantioselectivity using AuCl2 as catalyst and (R)-MeO-biphep as ligand (F. Liu, Y. Yu, J. Zhang Angew. Chem. Int. Ed. 2009, 48, 5505). In this report, the replacement of L3 by L1 (modification of the bite angle) or L2 (bulkier substituents on the phosphorous aryl moieties) allowed the synthesis of optically active furo[3,4-d][1,2]oxazines 3 in high yield and excellent diastereoselectivities. The choice of solvent was also crucial to keep high dia­stereoselectivity. The absolute configuration of products 3 was confirmed by single-crystal X-ray analysis.