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Enantioselective Catalytic [4+1]-Cyclization of ortho-Hydroxy-para-Quinone Methides with Allenoates |
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| Authors: | Katharina Zielke Ond?ej Ková? Michael Winter Dr Ji?í Pospí?il Prof Mario Waser |
| Institution: | 1. Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
These authors contributed equally to this work.;2. Department of Organic Chemistry, Faculty of Science, Palacky University, t?. 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic These authors contributed equally to this work.;3. Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria;4. Department of Organic Chemistry, Faculty of Science, Palacky University, t?. 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, ?lechtitel? 27, 78371 Olomouc, Czech Republic |
| Abstract: | The first highly asymmetric catalytic synthesis of densely functionalized dihydrobenzofurans is reported, which starts from ortho-hydroxy-containing para-quinone methides. The reaction relies on an unprecedented formal 4+1]-annulation of these quinone methides with allenoates in the presence of a commercially available chiral phosphine catalyst. The chiral dihydrobenzofurans were obtained as single diastereomers in yields up to 90 % and with enantiomeric ratios up to 95:5. |
| Keywords: | allenoates annulation diastereoselectivity enantioselectivity organocatalysis |