Anomalous Effect of α, α, α‐Trifluoroacetophenone Derivatives on a Conjugated Umpolung Reaction: Enantioselective Direct Self‐Annulation of Enals Catalyzed by a Chiral Cyclophane‐type N‐Heterocyclic Carbene. Issue 2 (15th January 2013)

• Record Type: Journal Article
• Authors: Ishida, Yasuhiro; Kawatsu, Kunihiro; Matsuoka, Yuki; Yamada, Kuniyo; Ikariya, Ryuichi; Sawayama, Jun; Hirao, Shotaro; Nishiwaki, Nagatoshi; Saigo, Kazuhiko
• Is Part Of: Asian journal of organic chemistry. Volume 2:Issue 2(2013:Feb.)
• Page Start: 140
• Page End: 144
• Publication Date: 2013-01-15
• Subjects: Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; 547.005
• DOI: 10.1002/ajoc.201200153
• Languages: English
• ISSNs: 2193-5807

Abstract

<abstract abstract-type="graphical" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p> <bold>Do it yourself</bold>: A broadly applicable, enantioselective, direct self‐annulation of enals is presented. An N‐heterocyclic carbene derived from a chiral cyclophane‐type imidazolium salt catalyzes the self‐annulation of cinnamaldehyde derivatives to afford the corresponding γ‐butyrolactones with up to 99 % <italic>ee.</italic> The use of α, α, α‐trifluoroacetophenone derivatives as cocatalysts was essential to obtain satisfactory yields and enantioselectivity.<boxed-text content-type="graphic" position="anchor" orientation="portrait"><graphic position="anchor" mimetype="image" xlink:href="ark:/27927/pgg1ts6vrkg" orientation="portrait" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /></boxed-text></p> </abstract>