Gold-catalyzed oxidations of propargyl alcohols with nitrones by using a P(tBu) (o-biphenyl)Au catalyst, afforded bicyclic annulation products from the Mannich reactions of gold enolates. The same reactions of propargyl amines with nitrones by using the same gold catalyst gave distinct oxoarylation products. Our DFT calculations indicate that oxidation of propargyl alcohols with nitrones by using electron-rich gold catalysts lead only to gold carbenes, which can generate gold enolates or oxoarylation intermediates with enolate species having a barrier smaller than that of oxoarylation species.
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http://dx.doi.org/10.1002/chem.202003840 | DOI Listing |
Org Lett
January 2025
Materials Tech Laboratory for Hydrogen & Energy Storage, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, Ningbo 315201, P. R. China.
A new sequential deprotonation strategy of dimethyl sulfoxide (DMSO) and propargyl alcohol in the presence of a base was developed for the generation of the α-hydroxyl carbanion, which enables rapid and controllable access to a wide range of valuable highly functionalized furans in one pot from alkynes and aldehydes under transition-metal- and additive-free conditions. Preliminary mechanistic studies revealed the crucial role of the base and DMSO. More importantly, deuterium labeling experiments confirmed the formation of the α-hydroxyl carbanion.
View Article and Find Full Text PDFOrg Lett
December 2024
Research Center for Molecular Recognition and Synthesis, Department of Chemistry, Fudan University, 220 Handan Lu, Shanghai 200433, People's Republic of China.
An efficient dehydrative coupling of propargylic alcohols with diarylphosphine oxides to construct tetrasubstituted allenylphosphoryl compounds in the presence of a Pd/Brønsted acid co-catalyst has been developed. As a benefit from the use of a Brønsted acid, this reaction could perform under mild conditions with excellent yields, accommodating a wide range of functional groups. The potential utility of this method has also been demonstrated.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
National and Local Joint Engineering Research Center of Biomedical Functional Materials, Jiangsu Key Laboratory of New Power Batteries, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China.
Deoxyfluorination is one of the most practical methods for introducing fluorine atoms, since hydroxyl groups are commonly found in organic small molecules. Traditional fluorination methods often rely on hazardous fluorinating reagents. Herein, we report the deoxyfluorination of propargyl alcohols using sulfur hexafluoride (SF) as a safe fluorinating agent under photocatalytic conditions.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin 300071, China.
The direct enantioselective functionalization of C(sp)-H bonds in organic molecules could fundamentally transform the synthesis of chiral molecules. In particular, the enantioselective oxidation of these bonds would dramatically change the production methods of chiral alcohols and esters, which are prevalent in natural products, pharmaceuticals, and fine chemicals. Remarkable advances have been made in the enantioselective construction of carbon-carbon and carbon-nitrogen bonds through the C(sp)-H bond functionalization.
View Article and Find Full Text PDFJ Org Chem
December 2024
Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, Changsha 410081, China.
The Cu(MeCN)PF-catalyzed reaction of 1-(2-hydroxyphenyl)-propargyl alcohols with aryl/alkyl mercaptan and subsequent treatment with KCO only offered 3-(alkylthio)benzofurans, whereas the stoichiometric-exceeding CuI-mediated reaction and subsequent treatment with DIPEA furnished 2-(alkylthiomethyl)benzofurans with high selectivity. The amount of Cu(I) salts plays a key role in selective formation. This unique protocol for the selective construction of the two series of benzofurans containing alkylthio group proved to be suitable for broad substrates and except for aliphatic alkynyl alcohols.
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