Catalytic Enantioselective Quick Route to Aldol‐Tethered 1,6‐ and 1,7‐Enynes from ω‐Unsaturated Aldehydes |
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Authors: | Prof. Dr. Jesús M. García Dr. José M. Odriozola Dr. Jesús Razkin Irati Lapuerta Amaiur Odriozola Iñaki Urruzuno Dr. Silvia Vera Prof. Dr. Mikel Oiarbide Prof. Dr. Claudio Palomo |
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Affiliation: | 1. Departamento de Química Aplicada, Universidad Pública de Navarra, Campus de Arrosadía, 31006 Pamplona (Spain);2. Departamento de Química Orgánica I, Universidad del País Vasco UPV/EHU, Manuel Lardizabal 3, 20018 San Sebastián (Spain), Fax: (+34)?943015270 |
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Abstract: | An effective asymmetric route to functionalized 1,6‐ and 1,7‐enynes has been developed based on a direct cross‐aldol reaction between ω‐unsaturated aldehydes and propargylic aldehydes (α,β‐ynals) promoted by combined α,α‐dialkylprolinol ether/Brønsted acid catalysis. This synergistic activation strategy is key to accessing the corresponding aldol adducts with high stereoselectivity, both enantio‐ and diastereoselectivity. The aldol reaction also proceeds well with propargylic ketones (α,β‐ynones) thus enabling a stereocontrolled access to the corresponding tertiary alcohols. The utility of these adducts, which are difficult to prepare through standard methodology, is demonstrated by their transformation into trisubstituted bicyclic enones using standard Pauson–Khand conditions. |
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Keywords: | aldol reaction enynes organocatalysis Pauson– Khand propargylic alcohols |
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