19015-37-3Relevant academic research and scientific papers
Palladium and Nickel Catalyzed Suzuki Cross-Coupling with Alkyl Fluorides
Balaraman, Kaluvu,Wolf, Christian
supporting information, p. 8994 - 8999 (2021/11/20)
Suzuki cross-coupling of benzylic and unactivated aliphatic fluorides with aryl- and alkenylboronic acids has been achieved via mechanistically distinct Pd and Ni catalyzed pathways that outperform competing protodeboronation, β-hydride elimination, and h
Boron insertion into alkyl ether bonds via zinc/nickel tandem catalysis
Lyu, Hairong,Kevlishvili, Ilia,Yu, Xuan,Liu, Peng,Dong, Guangbin
, (2021/04/30)
Mild methods to cleave the carbon-oxygen (C?O) bond in alkyl ethers could simplify chemical syntheses through the elaboration of these robust, readily available precursors. Here we report that dibromoboranes react with alkyl ethers in the presence of a nickel catalyst and zinc reductant to insert boron into the C?O bond. Subsequent reactivity can effect oxygen-to-nitrogen substitution or one-carbon homologation of cyclic ethers and more broadly streamline preparation of bioactive compounds. Mechanistic studies reveal a cleavage-then-rebound pathway via zinc/nickel tandem catalysis.
Chiral cyclometalated iridium complexes for asymmetric reduction reactions
Smith, Jennifer,Kacmaz, Aysecik,Wang, Chao,Villa-Marcos, Barbara,Xiao, Jianliang
supporting information, p. 279 - 284 (2021/01/18)
A series of chiral cyclometalated iridium complexes have been synthesised by cyclometalating chiral 2-aryl-oxazoline and imidazoline ligands with [Cp?IrCl2]2. These iridacycles were studied for asymmetric transfer hydrogenation reactions with formic acid as the hydrogen source and were found to display various activities and enantioselectivities, with the most effective ones affording up to 63% ee in the asymmetric reductive amination of ketones and 77% ee in the reduction of pyridinium ions. This journal is
A hydrogen borrowing annulation strategy for the stereocontrolled synthesis of saturated aza-heterocycles
Armstrong, Roly J.,Chamberlain, Anna E. R.,Donohoe, Timothy J.,Paterson, Kieran J.,Twin, Heather C.
supporting information, p. 3563 - 3566 (2020/04/03)
An iridium catalyzed method for the synthesis of saturated aza-heterocycles from amines and diols is reported. A wide range of substituted heterocycles can be obtained using this approach including products bearing substituents at the C2, C3 and C4 positions. Employing water as the solvent, enantiopure diols could undergo annulation with minimal racemization, enabling the synthesis of valuable enantioenriched C3 and C4-substituted saturated aza-heterocycles.
Transition-Metal-Free Deconstructive Lactamization of Piperidines
Romero-Iba?ez, Julio,Cruz-Gregorio, Silvano,Sandoval-Lira, Jacinto,Hernández-Pérez, Julio M.,Quintero, Leticia,Sartillo-Piscil, Fernando
supporting information, p. 8867 - 8871 (2019/05/28)
One of the major challenges in organic synthesis is the activation or deconstructive functionalization of unreactive C(sp3)–C(sp3) bonds, which requires using transition or precious metal catalysts. We present here an alternative: the deconstructive lactamization of piperidines without using transition metal catalysts. To this end, we use 3-alkoxyamino-2-piperidones, which were prepared from piperidines through a dual C(sp3)–H oxidation, as transitory intermediates. Experimental and theoretical studies confirm that this unprecedented lactamization occurs in a tandem manner involving an oxidative deamination of 3-alkoxyamino-2-piperidones to 3-keto-2-piperidones, followed by a regioselective Baeyer–Villiger oxidation to give N-carboxyanhydride intermediates, which finally undergo a spontaneous and concerted decarboxylative intramolecular translactamization.
Use of (cyclopentadienone)iron tricarbonyl complexes for c-n bond formation reactions between amines and alcohols
Brown, Thomas J.,Cumbes, Madeleine,Diorazio, Louis J.,Clarkson, Guy J.,Wills, Martin
, p. 10489 - 10503 (2018/05/31)
The application of a series of (cyclopentadienone)iron tricarbonyl complexes to "borrowing hydrogen" reactions between amines and alcohols was completed in order to assess their catalytic activity. The electronic variation of the aromatic groups flanking the C?O of the cyclopentadienone influenced the efficiency of the reactions; however, in other cases, the Kn?lker catalyst 1, containing trimethylsilyl groups flanking the cyclopentadienone ketone, gave the best results. In some cases, the change of the ratio of amine to alcohol improves the conversion significantly. The application of iron catalysts to the synthesis of a range of amines, including unsaturated amines, was investigated.
Cobalt-Catalyzed Cross-Coupling of 3- and 4-Iodopiperidines with Grignard Reagents
Gonnard, Laurine,Gurinot, Amandine,Cossy, Janine
, p. 12797 - 12803 (2015/09/01)
A cobalt-catalyzed cross-coupling between 3- and 4-iodopiperidines and Grignard reagents is disclosed. The reaction is an efficient, cheap, chemoselective, and flexible way to functionalize piperidines. This coupling was used as the key step to realize a short synthesis of (±)-preclamol. Some mechanistic investigations were conducted that highlight the formation of radical intermediates. Scaffold synthesis: A cobalt-catalyzed cross-coupling between iodopiperidines and Grignard reagents is reported (see scheme; PG=protecting group). A large variety of 3- and 4-substituted piperidines were synthesized and the method was applied to a short synthesis of (±)-preclamol. This work constitutes one of the rare examples of cross-couplings involving 3-halogeno piperidines.
Enantioselective Desymmetrization of Glutarimides Catalyzed by Oxazaborolidines Derived from cis-1-Amino-indan-2-ol
Kutama, Ibrahim U.,Jones, Simon
, p. 11468 - 11479 (2015/12/04)
Enantioselective reductive desymmetrization of glutarimides has been achieved employing an oxazaborolidine catalyst derived from cis-1-amino-indan-2-ol. The reaction was found to proceed through a stereoablative process that upgraded the enantioselectivity of an intermediate hydroxy-lactam. The reaction was generally tolerant of a number of substituents in the 4-position, giving enantiomeric excesses of greater than 82%.
Iron- and cobalt-catalyzed arylation of azetidines, pyrrolidines, and piperidines with grignard reagents
Barr, Baptiste,Gonnard, Laurine,Campagne, Rmy,Reymond, Sbastien,Marin, Julien,Ciapetti, Paola,Brellier, Marie,Gurinot, Amandine,Cossy, Janine
, p. 6160 - 6163 (2015/01/16)
Iron- and cobalt-catalyzed cross-couplings between iodo-azetidines, -pyrrolidines, -piperidines, and Grignard reagents are disclosed. The reaction is efficient, cheap, chemoselective and tolerates a large variety of (hetero)aryl Grignard reagents.
Iron-catalyzed cross-coupling of unactivated secondary alkyl thio ethers and sulfones with aryl grignard reagents
Denmark, Scott E.,Cresswell, Alexander J.
supporting information, p. 12593 - 12628 (2014/01/17)
The first systematic investigation of unactivated aliphatic sulfur compounds as electrophiles in transition-metal-catalyzed cross-coupling are described. Initial studies focused on discerning the structural and electronic features of the organosulfur substrate that enable the challenging oxidative addition to the C(sp3)-S bond. Through extensive optimization efforts, an Fe(acac)3-catalyzed cross-coupling of unactivated alkyl aryl thio ethers with aryl Grignard reagents was realized in which a nitrogen "directing group" on the S-aryl moiety of the thio ether served a critical role in facilitating the oxidative addition step. In addition, alkyl phenyl sulfones were found to be effective electrophiles in the Fe(acac) 3-catalyzed cross-coupling with aryl Grignard reagents. For the latter class of electrophile, a thorough assessment of the various reaction parameters revealed a dramatic enhancement in reaction efficiency with an excess of TMEDA (8.0 equiv). The optimized reaction protocol was used to evaluate the scope of the method with respect to both the organomagnesium nucleophile and sulfone electrophile.
