The asymmetric one-step net addition of unactivated propargylic C-H bond to aldehyde leads to an atom-economic construction of versatile chiral propargylic alcohols but has not been realized previously. Here we show its implementation in an intramolecular manner under mild reaction conditions. Via cooperative gold catalysis enabled by a chiral bifunctional phosphine ligand, this chemistry achieves asymmetric catalytic deprotonation of propargylic C-H (pK > 30) by a tertiary amine group (pK ~ 10) of the ligand in the presence of much more acidic aldehydic α-hydrogens (pKa ~ 17). The reaction exhibits a broad scope and readily accommodates various functional groups. The 5-/6-membered ring fused homopropargylic alcohol products are formed with excellent enantiomeric excesses and high selectivities with or without a preexisting substrate chiral center. DFT studies of the reaction support the conceived reaction mechanism and the calculated energetics corroborate the observed stereoselectivity and confirm an additional metal-ligand cooperation.
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http://dx.doi.org/10.1038/s41929-020-00569-8 | DOI Listing |
J Am Chem Soc
January 2025
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
January 2025
School of Chemistry and Chemical Engineering, Linyi University, The middle of Shuangling Road, Linyi, Shandong 276000, People's Republic of China.
Two novel Pd-catalyzed protocols for the controllable synthesis of benzo[]furo[2,3-]azepines and furo[3,2-]indoles have been developed by intermolecular oxidative annulation of 2-(furan-2-yl)anilines and propargyl carbonates versus intramolecular C-H amination reactions. These two protocols feature great scalability, functional group tolerance, and relatively mild reaction conditions. Notably, the robust methodologies could also provide valuable opportunities for assembling azepine-fused benzothiophene, indole-fused benzothiophene, and indole-fused benzimidazole, which may have potential applications in the synthesis of related pharmaceuticals or polymeric materials.
View Article and Find Full Text PDFOrg Lett
December 2024
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China.
The fused eight-membered carbocycles (EMCs) play vital roles in the medicinal and biological investigations of many natural products and marketed drugs. The traditional synthesis of [6-8-6] benzo-fused derivatives involves multistep reactions and low yields, making the development of a one-step synthesis method a more challenging work. Here, we present a novel strategy for one-step construction of [6-8-6] benzo-fused scaffold from propargyl diazoacetates substituted with benzyl-nitrogen heterocyclic ring via Rh(ll)-catalyzed carbene/alkyne metathesis (CAM) and selective C-H bond insertion.
View Article and Find Full Text PDFOrg Lett
November 2024
School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China.
An efficient FLP-mediated cycloisomerization is described, providing easy access to quinolinium and chromenylium derivatives by treatment of readily available propargylanilines and aryl propargyl ethers with Lewis acidic boranes, respectively. The reaction proceeds via a 6--dig cyclization/dehydrogenation sequence. The heteroatom functions serve as Lewis bases in combination with Lewis acidic boranes to effect synergistic activation of an alkynyl triple bond and a C-H bond.
View Article and Find Full Text PDFJ Org Chem
December 2024
College of Chemistry & Materials Science, Northwest University, Xi'an 710127, P. R. China.
This study provides a practical route to synthesize tetrasubstituted alkenes that involves Co(III)-catalyzed C-H bond activation and regioselective insertion of the alkyne, followed by chelation of the substrate hydroxyl to Co and migration of the pyridine group. Density functional theory studies revealed the origin of regioselectivity and elucidated the crucial role of the hydroxyl group for the migration of pyridine. The method can be conducted on a gram scale, is compatible with a wide range of substrates, and has a high functional group tolerance.
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