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Synfacts 2008(7): 0689-0689
DOI: 10.1055/s-2008-1078469
DOI: 10.1055/s-2008-1078469
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York
Synthesis of Benzofurans via Aryne-Iodonium Ylide Cycloaddition
X.-C. Huang, Y.-L. Liu, Y. Liang*, S.-F. Pi, F. Wang, J.-H. Li*
Hunan Normal University and Hunan University, Changsha, P. R. of China
Further Information
Publication History
Publication Date:
20 June 2008 (online)

Significance
o-Silyl aryltriflates, converted into benzynes in situ under mild conditions, undergo cycloaddition with iodonium ylides to yield benzofuran derivatives. A similar process was reported over 30 years ago by Caubere and co-workers from dihalobenzenes and cyclic ketone enolates (P. Caubere et al. J. Org. Chem. 1975, 40, 2853), but the conditions used were much harsher (NaNH2 + NaOt-Bu). The reaction scope was well studied and the yields are generally fair to good, except when R2 = sterically demanding groups, such as 2-IC6H4 (32% yield). A ca. 1:1 mixture of products arises when R1 = 4-Me.