The preparation of O-octadecyl-S-chlorodifluoromethyl xanthate from chlorodifluoroacetic acid and its use as a convenient source of chlordifluoromethyl radicals is described. This reagent may be used to access gem-difluoroalkenes and -dienes, as well as (2,2-difluoroethyl)indolines, -indoles, and -naphthols.
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http://dx.doi.org/10.1021/ol501063a | DOI Listing |
Org Lett
August 2023
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR 999077, China.
A highly diastereoselective Pd(0)-catalyzed Mizoroki-Heck reaction of -difluoroalkenes is described. Unlike previously reported C-F bond functionalization with organometallic reagents, this reaction takes place between two different alkenes to achieve a formal C-F and C-H bond cross-coupling via a distinct pathway. Monofluorinated 1,3-diene products can be synthesized with control of the geometry of each alkene and good functional group tolerability.
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June 2023
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
The stereoselective C-F bond borylation of tetrasubstituted β,β-difluoroacrylates has been achieved. In contrast to the previously used Bpin reagent, which only led to dimerization products, this work employs the unsymmetrical diboron reagent (pin)B-B(dan) under the palladium(0)-catalyzed conditions to access novel boronamides containing the monofluorinated vinyl-B(dan) functionality. These compounds can cross-couple directly with -difluoroalkenes without reactivation in Suzuki-Miyaura reactions to afford vincinal difluoro 1,3-dienes with modular control of the substituents.
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June 2023
State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, Shandong, P. R. China.
Herein we develop a Ni-catalyzed defluorinative cross-electrophile coupling of -difluoroalkenes with alkenyl electrophiles that allowed the generation of C(sp)-C(sp) bonds. The reaction provided various monofluoro 1,3-dienes with broad functional group compatibility and excellent stereoselectivity. Synthetic transformations and applications to the modification of complex compounds were also demonstrated.
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August 2022
Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Center for Excellence in Molecular Synthesis of CAS, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
-Difluoroalkenes (=CF), which normally act as metabolically stable bioisosteres for carbonyl groups (C═O), are widely applied in agrochemicals and pharmaceuticals and are also used as building blocks in organic synthesis. Herein, an example of Cu/Pd-catalyzed borodifluorovinylation was achieved using alkynes, difluoroethylene bromide, and Bpin as chemical feedstocks, providing the corresponding conjugated -difluoroalkene scaffold with good functional group compatibility. Moreover, an array of fluorinated synthons can be obtained through further transformations.
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October 2021
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR 999077, China.
We herein describe a Pd-catalyzed stereoselective C-F bond vinylation and allylation reaction of tetrasubstituted -difluoroalkenes for the synthesis of valuable monofluorinated 1,3- and 1,4-dienes with excellent diastereoselectivities. Different from previously used Pd(PPh), a catalytic system involving Pd(0) and dppe as the ligand was developed for Stille-type cross-coupling between -difluoroalkenes and vinyl- and allyltin reagents.
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