C'mon 1,2-dione: A new diastereo- and enantioselective Lewis base catalyzed domino Michael/aldol reaction converts alpha,beta-unsaturated aldehydes and 1,2-diones into chiral bicyclo[3.2.1]octane-6-carbaldehydes. The products are produced in good to excellent enantioselectivities (90-98 % ee) and can be transformed into bicyclic diols and triols. Additionally, a retro-aldol cyclization provides access to valuable tetrahydrochromenones (see scheme).
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http://dx.doi.org/10.1002/anie.200900754 | DOI Listing |
Chem Sci
April 2024
Department of Chemistry, Graduate School of Science, Tohoku University Sendai 980-8578 Japan
Highly substituted -hydrindanes were synthesized by the three-component coupling reactions of 1,3-diethyl 2-(2-oxopropylidene)propanedioate and two different α,β-unsaturated aldehydes catalyzed by diphenylprolinol silyl ether. The reaction proceeds two successive independent catalytic domino reactions in a one-pot reaction by a single chiral catalyst. Domino reactions involve Michael/Michael and Michael/aldol reactions to afford -hydrindanes with excellent diastereoselectivity and nearly optically pure form.
View Article and Find Full Text PDFJ Org Chem
April 2024
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States.
Michael-aldol domino reactions are powerful tools for rapidly assembling carbocyclic scaffolds. We herein disclose a base-catalyzed Michael-aldol domino reaction of trisubstituted Michael acceptors with β-keto ester nucleophiles. The cyclohexanone products are obtained in excellent diastereoselectivity (up to >20:1 dr) and good yields (up to 84%).
View Article and Find Full Text PDFOrg Biomol Chem
April 2024
INSA Rouen Normandie, Univ Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000 Rouen, France.
A domino Vinylogous aza-Michael-Aldol-Cyclocondensation (aza-VMAC) reaction was achieved with a series of alkylidene Meldrum's acid derivatives under simple operational conditions paving the way to novel pyrano[2,3-]pyrroles in an excellent diasteroselectivity (>96 : 4), encompassing the relative control of three contiguous stereocenters.
View Article and Find Full Text PDFJ Org Chem
January 2024
School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Xinjiang, Shihezi 832003, China.
Catalytic and asymmetric domino Michael/aldol reaction of 1,2-dicarbonyl compounds with α,β-unsaturated ketones under the synergetic catalysis of chiral-at-metal rhodium complexes and pyrrolidine to deliver tertiary α-hydroxylation-cyclopentanones (45-89% yields with 81-99% ee and up to >20:1 dr) bearing three contiguous stereogenic centers had been established. Moreover, the scalability and practical utility of this protocol were well demonstrated by employing a gram-scale reaction and some representative transformations.
View Article and Find Full Text PDFOrg Biomol Chem
August 2023
State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Guangzhou 510530, China.
A highly enantio- and diastereoselective domino thia-Michael/aldol reaction applying 5-dibenzo[,][7]annulen-5-one as a Michael acceptor, catalyzed by a chiral phosphoric acid (CPA), has been developed. The bridged biaryl adduct contains multiple stereogenic centers in the bridging linkage as well as a thermodynamically controlled stereogenic axis. The energy difference between the two atropodiastereomers is about 9.
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