The enantioselective intramolecular [2 + 2 + 2] cycloaddition of various enediynes, where two acetylenic moieties are connected by a trans-olefinic moiety, gave chiral tricyclic cyclohexa-1,3-dienes using Rh-H8-BINAP catalyst. In the case of carbon-atom-tethered enediynes, enantioselectivity was generally good-to-high regardless of the substituents on their alkyne termini. In contrast, with heteroatom-tethered enediynes, appropriate substituents were required to induce the oxidative coupling of alkyne and alkene moieties before that of two alkyne moieties, which would be important for highly enantioselective intramolecular cycloaddition.
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http://dx.doi.org/10.1021/jo070762d | DOI Listing |
RSC Adv
January 2025
Department of Organic Chemistry, Faculty of Chemistry Urmia University Urmia Iran.
Benzo-fused γ-lactams are fundamental in medicinal chemistry, acting as essential elements for various therapeutic agents due to their structural adaptability and capability to enhance biological activity. In their synthesis, transition metals play a pivotal role as catalysts, offering more efficient alternatives to traditional methods by facilitating C-N bond formation through mechanisms like intramolecular coupling. Recent advances have especially spotlighted transition-metal-catalyzed C-H amination reactions for directly converting C(sp)-H to C(sp)-N bonds, streamlining the creation of these compounds.
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry, Memorial University, St. John's, Newfoundland and Labrador A1B 3X7, Canada.
Organocatalytic, enantioselective decarboxylative Mannich reactions of α,β-unsaturated β'-ketoacids and isatin -Boc imines, to give the corresponding 3-carbamoyl-2-oxindole derivatives, were developed. Subsequent N-deprotection and diastereoselective, intramolecular, aza-Michael reaction of the free amine provides previously unreported spiro[indoline-3,2'-piperidine]-2,4'-diones.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Shenzhen Grubbs Institute and Department of Chemistry, Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
ConspectusChiral organosilicon compounds bearing a Si-stereogenic center have attracted increasing attention in various scientific communities and appear to be a topic of high current relevance in modern organic chemistry, given their versatile utility as chiral building blocks, chiral reagents, chiral auxiliaries, and chiral catalysts. Historically, access to these non-natural Si-stereogenic silanes mainly relies on resolution, whereas their asymmetric synthetic methods dramatically lagged compared to their carbon counterparts. Over the past two decades, transition-metal-catalyzed desymmetrization of prochiral organosilanes has emerged as an effective tool for the synthesis of enantioenriched Si-stereogenic silanes.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Department of Applied Chemistry, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, and Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Agricultural University, Hefei 230036, China.
A high-performance anionic stereogenic-at-cobalt(III) complex/oxone catalytic system was developed for various enantioselective intramolecular halocyclizations of olefins using halide salts as halogen sources, delivering structurally diverse halogenated heterocyclic compounds with outstanding stereoselectivity (up to 97 : 3 e.r.).
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States.
ConspectusThe manipulation of strained rings is a powerful strategy for accessing the valuable chemical frameworks present in natural products and active pharmaceutical ingredients. Aziridines, the smallest N-containing heterocycles, have long served as building blocks for constructing more complex amine-containing scaffolds. Traditionally, the reactivity of typical aziridines has been focused on ring-opening by nucleophiles or the formation of 1,3-dipoles.
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