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or enolate geometry is the primary determinant of diastereoselectivity in the aldol reaction. Although amide and thioamide enolates are anticipated to have predominantly the geometry because of the intrinsic steric demand, spectroscopic confirmation of the geometry in solution has remained elusive, particularly in the realm of highly stereoselective catalytic asymmetric aldol reactions. Herein we demonstrate that the 7-azaindoline auxiliary enables direct observation of the exclusive formation of the -enolate of the thioamide en route to a highly -selective aldol reaction.
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http://dx.doi.org/10.1021/acs.orglett.9b04120 | DOI Listing |
Org Biomol Chem
September 2025
Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Pune-410008, India.
A facile and efficient one-pot rongalite-mediated self-dimerization of 3-acylidene-2-oxindoles has been developed for the diastereoselective synthesis of highly functionalized dispirocyclopentanebisoxindoles. The reaction proceeds a domino sequence involving intermolecular Michael addition followed by intramolecular aldol cyclization under basic conditions. Rongalite, an inexpensive and readily available reagent (∼$0.
View Article and Find Full Text PDFJ Chem Phys
September 2025
Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
The formation of carbinolamine represents the crucial initial step in the aldol reaction, specifically involving the interaction between p-nitrobenzaldehyde and acetone, facilitated by amine-catalyzed mesoporous silica nanoparticles (amine-MSN). In this process, a nitrogen atom from propylamine, which acts as the catalytic moiety, engages in the formation of a covalent bond with a carbon atom from acetone, leading to the generation of a carbinolamine intermediate. This reaction is significantly influenced by the presence of silanol groups located on the surface of the amine-MSN, which contribute to the catalytic activity.
View Article and Find Full Text PDFOrg Lett
September 2025
School of Science and Engineering, Shenzhen Key Laboratory of Innovative Drug Synthesis, The Chinese University of Hong Kong, Shenzhen, Shenzhen 518172, P. R. China.
The first asymmetric total synthesis of 5,10-seco-neoansamycin A, a 19-membered cyclic octaketide, was achieved in 20 steps (with several steps being telescoped) and 6.7% overall yield starting from the reported compound, thus leading to the assignment of its absolute configuration. This convergent synthetic approach features late-stage macrolactamization, a judicious application of an asymmetric aldol reaction.
View Article and Find Full Text PDFRSC Adv
August 2025
Natural and Medical Sciences Research Center, University of Nizwa P.O. Box 33, Postal Code 616, Birkat Al Mauz Nizwa Sultanate of Oman.
A new series of dihydronaphthalen-1(2)-one derivatives were synthesized in high yields starting from commercially available 3,5,5-trimethylcyclohex-2-en-1-one 1a, aromatic aldehydes 2, and diethyl acetylenedicarboxylate. Reaction of 1a with the aldehydes produced the respective dienones 3, which could cycloadd to dialkyl acetylenedicarboxylate, either stepwise or , under aqueous/organocatalyzed (DMAP) conditions. The respective adducts 4, were produced efficiently a Diels-Alder-double bond isomerization-oxidative aromatization sequence and were characterized based on the analysis of their H and C NMR spectra.
View Article and Find Full Text PDFOrg Lett
September 2025
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, P. R. China.
We report herein the first reductive alkylation/aldol reaction via dual nickel/photoredox catalysis. This catalytic strategy completes the traditional approaches that require the performance of reactive organometallic reagents. By the simple assembly of unactivated alkyl halides, α,β-unsaturated carbonyls, and aldehydes in one-pot reaction, a variety of synthetically valuable β-hydroxyl carbonyl compounds can be synthesized under mild conditions with moderate to good yields.
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