Atom-Transfer Tandem Radical Cyclization Reactions Promoted by Lewis Acids†
Dan Yang Prof.
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorShen Gu
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorYi-Long Yan
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorHong-Wu Zhao
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorNian-Yong Zhu
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorDan Yang Prof.
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorShen Gu
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorYi-Long Yan
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorHong-Wu Zhao
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorNian-Yong Zhu
Department of Chemistry, The University of Hong Kong Pokfulam Road, Hong Kong (P. R. China) Fax: (+852) 2859-2159
Search for more papers by this authorThis work was supported by The University of Hong Kong and the Hong Kong Research Grants Council. D.Y. acknowledges the Bristol-Myers Squibb Foundation for an Unrestricted Grant in Synthetic Organic Chemistry and the Croucher Foundation for a Croucher Senior Research Fellowship.
Graphical Abstract
Various polycyclic ring skeletons (e.g. 3) are formed from unsaturated α-bromo β-keto esters (e.g. 1) in a Lewis acid catalyzed atom-transfer tandem radical-cyclization reaction in moderate to good yields and with excellent stereoselectivities. Furthermore, in the presence of chiral complexes such as [Yb(Ph-pybox)(OTf)3] (2), the enantioselective cyclization gave up to 84 % ee. OTf = trifluoromethanesulfonate, pybox = 2,6-bis(2-oxazolin-2-yl)pyridine.
Supporting Information
Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2002/z18697_s.pdf or from the author.
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