Allene-(E)-ene-yne N-tosyl-tethered substrates 3 a-3 h were efficiently prepared and their rhodium-catalyzed [2+2+2] cycloaddition reactions were evaluated. The cycloadditions are chemoselective as only the proximal double bond of the allene reacted to afford exocyclic double bonds in the fused-tricyclic scaffolds. The stereoselectivity depended on the catalytic system used. Reactivity between allene, alkene, and alkyne was studied for the first time by density functional theory calculations. This mechanistic study determines the order in which the unsaturated groups take part in the catalytic cycle.
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http://dx.doi.org/10.1002/chem.201703194 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Anhui Normal University, School of Chemistry and Materials Science, 189 Jiuhua South Road, 241002, Wuhu, CHINA.
Achieving axially chiral biaryl dialdehydes through asymmetric catalysis remains significantly challenging due to the lack of efficient strategies. In this report, we developed a rhodium-catalyzed enantioselective C-H amidation through chiral transient directing group strategy. With this new approach, a series of axially chiral amido dialdehydes were achieved in up to 86% yields with 99.
View Article and Find Full Text PDFMolecules
January 2025
School of Chemistry and Materials Engineering, Huainan Normal University, Huainan 232038, China.
Efficient access to pyranoisoquinoline derivatives via rhodium-catalyzed double C-H functionalization of phenyl oxadiazoles and diazo compounds has been developed. Two C-C bonds and one C-O and C-N bond formation was realized by this tandem reaction, along with the formation of two heterocycles, affording diversified pyran-fused isoquinolines in moderate to good yields with broad functional group tolerance under mild reaction conditions.
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry, School of Science, China Pharmaceutical University, Nanjing 211198, People's Republic of China.
The development and enantioselective synthesis of two types of -symmetric spirobi[dihydrophenalene] structures is reported. The reaction proceeds via rhodium-catalyzed 2-fold asymmetric conjugate arylation of dienones followed by BF·OEt-promoted spirocyclization to give the enantiopure spiro products. Additive-dependent chemodivergent synthesis of 3,3'-diarylated 2,2',3,3'-tetrahydro-1,1'-spirobi[phenalene]-9,9'-diols (3,3'-Ar-SPHENOLs) and the corresponding spiro diary ethers from the same intermediate is achieved.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China.
Rhodium-catalyzed regio- and enantioselective allylic arylation of racemic alkyl- and aryl- substituted allylic carbonates with arylboronic acids using commercially available BIBOP ligand is reported. This reaction proceeds at room temperature without base or other additive to deliver allylic arylation products in excellent yields, regio- and enantioselectivity (up to 95 % yield, >20 : 1 b/l, >99 % ee). Rh/BIBOP is disclosed as an efficient catalytic system for allylic substitution reaction.
View Article and Find Full Text PDFOrg Lett
January 2025
Pfizer Oncology Medicinal Chemistry, 10770 Science Center Drive, San Diego, California 92121, United States.
General procedures for the rhodium-catalyzed annulation of aryl/heteroaryl -pivaloyl hydroxamic acids and norbornadiene have been developed. Employing norbornadiene as an acetylene equivalent enables utilization of diverse heterocyclic substrates for this transformation which fail to react or undergo competitive Lossen rearrangement under previously reported conditions. Microwave heating significantly reduces reaction times compared to conventional protocols and allows a one-step process to be realized.
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