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L-Proline/CoCl2-catalyzed highly diastereo- and enantioselective direct aldol reactions.
Chemistry. 2011 Sep 19; 17(39):11024-9.C

Abstract

The CoCl(2)/L-proline (1:2) system was found to be an excellent catalyst for direct aldol reactions. Excellent yields (up to 93%) and a significant improvement in diastereoselectivity (anti/syn up to 45:1) as well as enantioselectivity (up to more than 99% ee) compared with using proline as the sole catalyst were observed. This catalyst system was successfully applied to both cyclic and acyclic ketones in combination with aromatic and aliphatic aldehydes. In situ chelation of CoCl(2) and proline (1:2) is proposed to promote the reaction through a six-membered Zimmermann-Traxler type transition state involving the positioning of proline-enamine and the aldehyde through chelation to Co(II).

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Publisher Full Text (DOI)

Authors+Show Affiliations

Karmakar A
Institut für Organische Chemie, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany.
Maji T
No affiliation info available
Wittmann S
No affiliation info available
Reiser O
No affiliation info available

MeSH

AlcoholsAldehydesCatalysisCobaltKetonesProlineStereoisomerism

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21932236

Citation

Karmakar, Ananta, et al. "L-Proline/CoCl2-catalyzed Highly Diastereo- and Enantioselective Direct Aldol Reactions." Chemistry (Weinheim an Der Bergstrasse, Germany), vol. 17, no. 39, 2011, pp. 11024-9.
Karmakar A, Maji T, Wittmann S, et al. L-Proline/CoCl2-catalyzed highly diastereo- and enantioselective direct aldol reactions. Chemistry. 2011;17(39):11024-9.
Karmakar, A., Maji, T., Wittmann, S., & Reiser, O. (2011). L-Proline/CoCl2-catalyzed highly diastereo- and enantioselective direct aldol reactions. Chemistry (Weinheim an Der Bergstrasse, Germany), 17(39), 11024-9. https://doi.org/10.1002/chem.201101299
Karmakar A, et al. L-Proline/CoCl2-catalyzed Highly Diastereo- and Enantioselective Direct Aldol Reactions. Chemistry. 2011 Sep 19;17(39):11024-9. PubMed PMID: 21932236.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - L-Proline/CoCl2-catalyzed highly diastereo- and enantioselective direct aldol reactions. AU - Karmakar,Ananta, AU - Maji,Tapan, AU - Wittmann,Sebastian, AU - Reiser,Oliver, PY - 2011/9/21/entrez PY - 2011/9/21/pubmed PY - 2012/1/10/medline SP - 11024 EP - 9 JF - Chemistry (Weinheim an der Bergstrasse, Germany) JO - Chemistry VL - 17 IS - 39 N2 - The CoCl(2)/L-proline (1:2) system was found to be an excellent catalyst for direct aldol reactions. Excellent yields (up to 93%) and a significant improvement in diastereoselectivity (anti/syn up to 45:1) as well as enantioselectivity (up to more than 99% ee) compared with using proline as the sole catalyst were observed. This catalyst system was successfully applied to both cyclic and acyclic ketones in combination with aromatic and aliphatic aldehydes. In situ chelation of CoCl(2) and proline (1:2) is proposed to promote the reaction through a six-membered Zimmermann-Traxler type transition state involving the positioning of proline-enamine and the aldehyde through chelation to Co(II). SN - 1521-3765 UR - https://www.unboundmedicine.com/medline/citation/21932236/L_Proline/CoCl2_catalyzed_highly_diastereo__and_enantioselective_direct_aldol_reactions_ L2 - https://doi.org/10.1002/chem.201101299 DB - PRIME DP - Unbound Medicine ER -