118416-05-0Relevant articles and documents
Cooperative Lewis Acid Catalysis for the Enantioselective C(sp3)-H Bond Functionalizations of 2-Alkyl Azaarenes
Rai, Pramod,Waiba, Satyadeep,Maji, Kakoli,Sahoo, Dibyaranjan,Maji, Biplab
supporting information, p. 8888 - 8893 (2021/11/24)
Herein, we describe the enantioselective C(sp3)-H bond functionalizations of 2-alkyl azaarenes using a cooperative dual Lewis acid catalysis. An achiral Lewis acid activates the unactivated azaarene partner without the need for a strong base. Orthogonally, a chiral-at-metal Lewis acid catalyst enables LUMO lowering and induces chirality. This method tolerates a range of complex molecular scaffolds and exhibits good to excellent yields and selectivity while accepting a wide variety of functional groups.
Modular Design of G-Quadruplex MetalloDNAzymes for Catalytic C-C Bond Formations with Switchable Enantioselectivity
Punt, Philip M.,Langenberg, Marie D.,Altan, Okan,Clever, Guido H.
supporting information, p. 3555 - 3561 (2021/04/07)
Metal-binding DNA structures with catalytic function are receiving increasing interest. Although a number of metalloDNAzymes have been reported to be highly efficient, the exact coordination/position of their catalytic metal center is often unknown. Here, we present a new approach to rationally develop metalloDNAzymes for Lewis acid-catalyzed reactions such as enantioselective Michael additions. Our strategy relies on the predictable folding patterns of unimolecular DNA G-quadruplexes, combined with the concept of metal-mediated base-pairing. Transition-metal coordination environments were created in G-quadruplex loop regions, accessible by substrates. Therefore, protein-inspired imidazole ligandoside L was covalently incorporated into a series of G-rich DNA strands by solid-phase synthesis. Iterative rounds of DNA sequence design and catalytic assays allowed us to select tailored metalloDNAzymes giving high conversions and excellent enantioselectivities (≥99%). Based on their primary sequence, folding pattern, and metal coordination mode, valuable information on structure-activity relationships could be extracted. Variation of the number and position of ligand L within the sequence allowed us to control the formation of (S) and (R) enantiomeric reaction products, respectively.
Asymmetric Synthesis of Multi-Substituted Tetrahydrofurans via Palladium/Rhodium Synergistic Catalyzed [3+2] Decarboxylative Cycloaddition of Vinylethylene Carbonates
Ming, Siliang,Qurban, Saira,Du, Yu,Su, Weiping
supporting information, p. 12742 - 12746 (2021/07/28)
Unlike the comprehensive development of tandem multi-metallic catalysis, bimetallic synergistic catalysis has been challenging to achieve high stereoselectivity with the generation of multi-stereogenic centers. Herein, an efficient synergistic catalysis for the diastereo- and enantioselective synthesis of multi-substituted tetrahydrofuran derivatives has been developed. Under mild reaction conditions, a series of target molecules with three consecutive stereocenters were synthesized by a palladium(0)/rhodium(III) bimetal-catalyzed asymmetric decarboxylative [3+2]-cycloaddition of vinylethylene carbonates with α,β-unsaturated carbonyl compounds. The corresponding adducts were obtained with moderate to high yields (67 %～98 %) and excellent stereoselectivities (>20 : 1 d.r., up to 99 % ee).
SYNTHESES OF α,β-UNSATURATED KETONES STARTING FROM VINYLIC AND ALLYLIC GRIGNARD REAGENTS VIA 2-IMIDAZOLYLMETHANOL INTERMEDIATES
Hayakawa, Satoshi,Michiue, Tohru,Okamoto, Masao,Hatakeyama, Shoko,Ohta, Shunsaku
, p. 457 - 474 (2007/10/02)
Various α,β-unsaturated ketones (9, 12 and 16) were prepared from 2-alkanol-1-methyl-1H-imidazoles (6, 10 and 13, respectively), which were obtained by treatment of 2-acyl-1-methyl-1H-imidazoles (1) with vinylic Grignard reagents, a lithium acetylide and allylic Grignard reagents, respectively. dl-(ar)-Turmerone (16i) was also synthesized as an application of the present methodology.
