By consideration of the mechanism of Pd-catalyzed cyclopropanation and allylation, NHC-pyridine compounds were adopted as the ligand in Pd-catalyzed cyclopropanation of esters and monosubstituted allylic reagents. The corresponding cyclopropanes were afforded as major products in moderate to good yields with high cyclopropane/allylation selectivity.
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http://dx.doi.org/10.1021/jo5018712 | DOI Listing |
Chem Asian J
January 2025
West China School of Public Health and West China Fourth Hospital, West China-PUMC C.C. Chen Institute of Health, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, 610041.
A photopromoted Pd-catalyzed Heck reaction of gem-difluorocyclopropyl bromides (DFCBs) with styrenes to deliver vinyl gem-difluorinated cyclopropanes (VDFCs) under mild conditions has been developed. The reaction demonstrates good functional group compatibility while providing high E/Z ratio of the products. Furthermore, the desired VDFCs can be easily transformed into fluorinated cyclic/acyclic architectures, which may broaden its applications in organic synthesis.
View Article and Find Full Text PDFTetrahedron Lett
September 2024
Department of Chemistry, Occidental College, Los Angeles, California 90041, United States.
Herein, we report a mild palladium-catalyzed decarboxylative allylic alkylation of allyl ester-substituted isoindolinone substrates to afford a variety of 3,3-disubstituted isoindolinone derivatives. The decarboxylative coupling reaction tolerates a range of functional groups, including ketones and alkenyl halides, and does not require protection of the isoindolinone nitrogen. Additionally, the reaction was found to proceed in near-quantitative yield for most substrates evaluated.
View Article and Find Full Text PDFChem Asian J
June 2024
College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou Industrial Park, Suzhou, 215123, P. R. China.
We reported a chiral oxamide-phosphine ligand (COAP-Ph)-Pd-catalyzed asymmetric [3+2] cycloaddition reaction between vinyl cyclopropane compounds derived from 1,3-indanedione and 2-vinylcyclopropane-1,1-dicarboxylates with cyclic sulfonyl 1-azadienes. The corresponding reactions provided a series of enantiomerically active spiro cyclopentane-indandione and cyclopentane structures bearing three consecutive stereogenic centers in good yields with good diastereo- and enantioselectivity. The COAP-Pd complex serves not only to promote generation of chiral π-allyl-palladium intermediates and induce the asymmetry of the reaction, but also depress the background reaction.
View Article and Find Full Text PDFOrg Biomol Chem
April 2024
Kobe Pharmaceutical University, Motoyamakita, Higashinada, Kobe 658-8558, Japan.
Despite their utility as directing groups, the C-C bond cleavage of cyclopropanes utilizing hydrazones has not been explored. Herein, Pd-catalyzed C-C bond cleavage reaction of -cyclopropyl acylhydrazones, followed by cycloisomerization to yield pyrazoles, has been developed. The protocol enables the synthesis of various α-pyrazole carbonyl compounds, which have a potential of biological activity.
View Article and Find Full Text PDFChem Commun (Camb)
April 2024
West China School of Public Health and West China Fourth Hospital, West China-PUMC C.C. Chen Institute of Health, and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China.
Small-ring chemistry is a fascinating field in organic chemistry. -Difluorinated cyclopropanes, a unique class of cyclopropanes, have garnered significant interest due to their intrinsic high reactivity. In this context, -difluorinated cyclopropanes have been extensively investigated as fluoroallylic synthons in Pd-catalyzed ring-opening/cross-coupling reactions for the synthesis of monofluoroalkenes with linear or branched selectivity.
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