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Chiral picolylamines for Michael and aldol reactions: probing substrate boundaries.
Org Biomol Chem. 2012 Dec 14; 10(46):9287-94.OB

Abstract

Here we report on inroads concerning increased substrate breadth via the picolylamine organocatalyst template, a vicinal chiral diamine based on a pyridine-primary amine motif. The addition of cyclohexanone to β-nitrostyrene has many catalyst solutions, but cyclopentanone and isobutyraldehyde additions continue to be challenging. PicAm-3 (10 mol%) readily allows the Michael addition of cyclopentanone or isobutyraldehyde (5.0 equiv.) to β-nitrostyrene derivatives. By contrast, PicAm-1 (7.0 mol%) is optimal for catalyzing the aldol reaction of cyclohexanone or cycloheptanone (3.3 equiv.) with aromatic aldehydes. Eighteen products are reported and for each reaction type new products are reported (4b-d, 9c). Very good yields and stereoselectivities are generally noted. The reactions, which require an acid additive, proceed via a transient chiral enamine and a mechanistic case is put forth for a bifunctional catalysis model.

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Publisher Full Text (DOI)

Authors+Show Affiliations

Nugent TC
Department of Chemistry, School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany. t.nugent@jacobs-university.de
Bibi A
No affiliation info available
Sadiq A
No affiliation info available
Shoaib M
No affiliation info available
Umar MN
No affiliation info available
Tehrani FN
No affiliation info available

MeSH

AldehydesCatalysisChromatography, High Pressure LiquidCyclohexanonesCyclopentanesDiaminesMolecular StructurePyridinesSpectrometry, Mass, Electrospray IonizationStereoisomerismStyrenes

Pub Type(s)

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

Language

eng

PubMed ID

23104278

Citation

Nugent, Thomas C., et al. "Chiral Picolylamines for Michael and Aldol Reactions: Probing Substrate Boundaries." Organic & Biomolecular Chemistry, vol. 10, no. 46, 2012, pp. 9287-94.
Nugent TC, Bibi A, Sadiq A, et al. Chiral picolylamines for Michael and aldol reactions: probing substrate boundaries. Org Biomol Chem. 2012;10(46):9287-94.
Nugent, T. C., Bibi, A., Sadiq, A., Shoaib, M., Umar, M. N., & Tehrani, F. N. (2012). Chiral picolylamines for Michael and aldol reactions: probing substrate boundaries. Organic & Biomolecular Chemistry, 10(46), 9287-94. https://doi.org/10.1039/c2ob26382c
Nugent TC, et al. Chiral Picolylamines for Michael and Aldol Reactions: Probing Substrate Boundaries. Org Biomol Chem. 2012 Dec 14;10(46):9287-94. PubMed PMID: 23104278.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Chiral picolylamines for Michael and aldol reactions: probing substrate boundaries. AU - Nugent,Thomas C, AU - Bibi,Ahtaram, AU - Sadiq,Abdul, AU - Shoaib,Mohammad, AU - Umar,M Naveed, AU - Tehrani,Foad N, Y1 - 2012/10/29/ PY - 2012/10/30/entrez PY - 2012/10/30/pubmed PY - 2013/4/2/medline SP - 9287 EP - 94 JF - Organic & biomolecular chemistry JO - Org Biomol Chem VL - 10 IS - 46 N2 - Here we report on inroads concerning increased substrate breadth via the picolylamine organocatalyst template, a vicinal chiral diamine based on a pyridine-primary amine motif. The addition of cyclohexanone to β-nitrostyrene has many catalyst solutions, but cyclopentanone and isobutyraldehyde additions continue to be challenging. PicAm-3 (10 mol%) readily allows the Michael addition of cyclopentanone or isobutyraldehyde (5.0 equiv.) to β-nitrostyrene derivatives. By contrast, PicAm-1 (7.0 mol%) is optimal for catalyzing the aldol reaction of cyclohexanone or cycloheptanone (3.3 equiv.) with aromatic aldehydes. Eighteen products are reported and for each reaction type new products are reported (4b-d, 9c). Very good yields and stereoselectivities are generally noted. The reactions, which require an acid additive, proceed via a transient chiral enamine and a mechanistic case is put forth for a bifunctional catalysis model. SN - 1477-0539 UR - https://www.unboundmedicine.com/medline/citation/23104278/Chiral_picolylamines_for_Michael_and_aldol_reactions:_probing_substrate_boundaries_ L2 - https://doi.org/10.1039/c2ob26382c DB - PRIME DP - Unbound Medicine ER -