Herein, we establish a remote hydrosulfonamidation (HSA) of alkenes using palladium catalysis, where -fluoro--(fluoro-sulfonyl)-carbamate with a sulfur(VI) fluoride moiety is demonstrated as a good amidation reagent. The -Markovnikov HSA reaction of terminal alkenes and the remote HSA of internal alkenes are achieved to efficiently yield primary -alkyl--(fluorosulfonyl)-carbamates. In addition, this protocol enables the high-value utilization of alkane by combining the dehydrogenation process.
View Article and Find Full Text PDFA novel Pd-catalyzed enantioselective aminochlorination of alkenes via a 6- cyclization is reported herein, which provides easy access to a wide array of structurally diverse 3-chloropiperidines in good yields with excellent enantioselectivities. Notably, both an electrophilic chlorination reagent (NCS) and the sterically bulky chiral pyridinyl-oxazoline (Pyox) ligand are crucial to the successful reaction.
View Article and Find Full Text PDFA ligand-controlled system has been disclosed for the regioselective palladium-catalyzed diamination of unactivated alkenes, which provides an easy access to a variety of amino-functionalized piperidines and pyrrolidines. The steric hindrance of ligands controlled the regioselectivtities of products. 6- diamination occurred with less sterically hindered quinox ligand to afford 3-aminopiperidines, while 5 diamination occurred with sterically bulky pyox ligand to give amino-substituted pyrrolidines.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2020
The first Pd-catalyzed enantioselective azidation of unactivated alkenes has been established by using readily accessible 1-azido-1,2-benziodoxol-3(1H)-one (ABX) as an azidating reagent, which affords a wide variety of structurally diverse 3-N -substituted piperidines in good yields with excellent enantioselectivity. The reaction features good functional-group compatibility and mild reaction conditions. Notably, both an electrophilic azidating reagent and the sterically bulky chiral pyridinyl-oxazoline (Pyox) ligand are crucial to the successful reaction.
View Article and Find Full Text PDFThe first asymmetric Pd -catalyzed aminofluorination of unactivated alkenes using chiral quinoline-oxazolines (Quox) as ligands has been developed. This reaction provides easy access to a wide array of enantiomerically enriched β-fluoropiperidines in good yields and with excellent enantioselectivity. Notably, Et NF⋅3 HF as a readily accessible nucleophilic fluoride source was found to play an essential role in the enantioselective control, and CsOCF also acts a key additive to improve the excellent ee value of products.
View Article and Find Full Text PDFA novel asymmetric 6-endo aminoacetoxylation of unactivated alkenes by palladium catalysis, which yields chiral β-acetoxylated piperidines with excellent chemo-, regio- and enantioselectivities under very mild reaction conditions, has been established herein by employing a new designed pyridine-oxazoline (Pyox) ligand. Importantly, introducing a sterically bulky group into the C-6 position of Pyox is crucial to enhance the reactivity of the aminoacetoxylation of alkenes.
View Article and Find Full Text PDFThis article describes the new economic decarboxylative trifluoromethylating reagent [Cu(phen)(O CCF )] (1; phen=1,10-phenanthroline) and the efficient difluorocarbene precursor [Cu(phen) ][O CCF Cl] (2). Treatment of copper tert-butoxide with phen and subsequent addition of trifluoroacetic acid or chlorodifluoroacetic acid afforded air-stable complexes 1 and 2, respectively, which were characterized by X-ray crystallography. The copper(I) ion in 1 is coordinated by a bidentate phen ligand, a monodentate trifluoroacetate group, and a molecule of CH CN in a distorted tetrahedral coordination geometry.
View Article and Find Full Text PDFA catalytic trifluoromethylselenolation of aryl and alkyl halides by a Cu(I) catalyst has been developed. A key intermediate, [(phen)Cu(SeCF3)]2 (5) was successfully isolated and characterized by X-ray diffraction. The important role of silver in the transmetalation process during the catalytic cycle was elucidated.
View Article and Find Full Text PDFThe development of new strategies for synthesis of trifluoromethylthiolate compounds is of considerable importance in pharmaceuticals, agrochemicals, and advanced materials. Accordingly, currently much attention is being devoted to the development of effective methods and reagents for their synthesis. In contrast, considerably less effort has been afforded to the development of preparing CSeCF3 bonds.
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