anti-5-Acetoxy-4-halo-alpha,beta-enoates undergo sequential or tandem reactions with two different magnesium cuprate reagents to afford anti-2,3-dialkyl-4,5-enoates in high chemical yield and with excellent diastereoselectivity. The one-pot tandem procedure can be achieved with 30 mol % of CuCN and affords a rapid stereoselective combinatorial approach to vicinal disubstituted gamma,delta-enoates containing functionality at either end of the carbon chain for subsequent functional group elaboration. The methodology should provide a powerful practical strategy for acyclic stereoselection.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ol800727f | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Isochroman-3,4-dione and Tandem Aerobic Oxidation of 4-Bromoisochroman-3-one in the Highly Regio- and Diastereoselective Diels-Alder Reaction for the Construction of Bridged Polycyclic Lactones.
J Org Chem
December 2024
Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno, 84084 Fisciano, SA, Italy.
Herein we report two processes facilitated by diisopropylethylamine (DIPEA) for the synthesis of novel bridged polycyclic molecule analogues to natural products. The use of 4-bromoisochroman-3-one initiated an autoxidation reaction, followed by a Diels-Alder cycloaddition in the presence of electron-deficient dienophiles. Mechanistic studies revealed isochromane-3,4-dione as a key intermediate, which undergoes in situ dienolization/dearomatization followed by a [4 + 2] cycloaddition.
View Article and Find Full Text PDFAsymmetric Vinylogous Michael/Oxa-Michael Tandem Reaction between β,γ-Unsaturated Amides and Isatin-Derived β,γ-Unsaturated α-Ketoesters.
J Org Chem
December 2024
Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
An organocatalytic asymmetric vinylogous Michael/oxa-Michael tandem reaction between β,γ-unsaturated pyrazoleamides and isatin-derived β,γ-unsaturated ketoesters has been developed with excellent regio-, diastereo-, and enantioselectivities. The methodology provides an effective approach to construct enantiomerically pure 3,4'-pyranyl spirooxindole derivatives containing three contiguous chiral centers. Moreover, the transformations of the chiral products, including the removal and reduction of the pyrazole group, have been investigated.
View Article and Find Full Text PDFNickel-Catalyzed Asymmetric (3 + 2) Annulations of Propargylic Carbonates and Vinylogous Donors via an Alkenylation Pathway.
J Am Chem Soc
November 2024
Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China.
The transition-metal-catalyzed alkenylation strategy of propargylic alcohol derivatives provides an efficient protocol to access multifunctional products in a double-nucleophilic attack pattern. While limited relevant asymmetric examples have been reported via palladium catalysis, here we first demonstrate that a nonprecious Ni(0)-based chiral complex can efficiently promote the tandem substitution process between propargylic carbonates and -trifluoroethyl ketimines via consecutive aza-vinylogous activations, finally accomplishing a (3 + 2) annulation reaction to afford products embedding a 4-methylene-3,4-dihydro-2-pyrrole framework with high regio-, diastereo-, and enantiocontrol. Their assemblies with a few all-carbon-based vinylogous precursors are also successful, and enantioenriched adducts containing a 3-methylenecyclopentene scaffold are furnished effectively.
View Article and Find Full Text PDFModification of natural compounds through biotransformation process by microorganisms and their pharmacological properties.
Fitoterapia
December 2024
State Key Laboratory Basis of Xinjiang Indigenous Medicinal Plants Resource Utilization, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China. Electronic address:
The biotransformation of natural compounds by fungal microorganisms is a complex biochemical process. Tandem whole-cell biotransformation offers a promising, alternative, and cost-effective method for modifying of bioactive novel compounds. This approach is particularly beneficial for structurally complex natural products that are difficult to be synthesized through traditional synthetic methods.
View Article and Find Full Text PDFCycloadditions of 4-Alkenyl-2-aminothiazoles with Nitroalkenes in the Formal Synthesis of Pramipexole: An Experimental and Computational Study.
J Org Chem
September 2024
Department of Organic Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Murcia 30100, Spain.
4-Alkenyl-2-dialkylaminothiazoles act as in-out dienes in [4 + 2] cycloaddition reactions with nitroalkenes, furnishing 2-amino-6-nitro-4,5,6,7-tetrahydrobenzothiazoles in moderate to good yields, accompanied by a subsequent 1,3- migration. These transformations proceed with exquisite site-, regio-, and diastereoselectivity. This strategy is further enriched by revealing a novel route for pramipexole synthesis.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!