25705-34-4Relevant academic research and scientific papers
Enantioselective synthesis of the strigolactone mimic (+)-GR24
Bromhead, Liam J.,Visser, Johan,McErlean, Christopher S. P.
, p. 1516 - 1520 (2014)
A short and cost-effective synthesis of the important strigolactone analogue (+)-GR24 is described. Central to this new approach is the concise, enantioselective synthesis of the A-C ring system.
Enhanced enantioselectivity in heterogeneous manganese-catalyzed asymmetric epoxidation with nanosheets modified amino acid Schiff bases as ligands by modulating the orientation and the arrangement order
An, Zhe,Han, Hongbo,He, Jing,Jiang, Yitao,Ping, Qi,Shu, Xin,Song, Hongyan,Tang, Yuanzhong,Wang, Wenlong,Xiang, Xu,Zhu, Yanru
, p. 22 - 36 (2021/08/25)
Catalytic enantioselective epoxidation of olefins plays an important role in the production of optically-active epoxy. Transition-metal complexes prove efficient for the catalytic epoxidation of un-functionalized olefins by employing privileged chiral lig
Regioselective biocatalytic self-sufficient Tishchenko-type reactionviaformal intramolecular hydride transfer
Buljubasic, Isa,Hall, Mélanie,Laggner, Olivia,Merusic, Kemal,Reiter, Tamara,Tassano, Erika,Vogel, Andreas
supporting information, p. 6340 - 6343 (2020/06/21)
A self-sufficient nicotinamide-dependent intramolecular bio-Tishchenko-type reaction was developed. The reaction is catalyzed by alcohol dehydrogenases and proceeds through formal intramolecular hydride transfer on dialdehydes to deliver lactones. Regioselectivity on [1,1′-biphenyl]-2,2′-dicarbaldehyde substrates could be controlledviathe electronic properties of the substituents. Preparative scale synthesis provided access to substituted dibenzo[c,e]oxepin-5(7H)-ones.
Pseudophedrine-Derived Myers Enolates: Structures and Influence of Lithium Chloride on Reactivity and Mechanism
Zhou, Yuhui,Jermaks, Janis,Keresztes, Ivan,MacMillan, Samantha N.,Collum, David B.
supporting information, p. 5444 - 5460 (2019/03/29)
The structures and reactivities of pseudoephedrine-derived dianionic Myers enolates are examined. A combination of NMR and IR spectroscopic, crystallographic, and computational data reveal that the homoaggregated dianions form octalithiated tetramers displaying S4-symmetric Li8O8 cores and overall C2 symmetry. Computational and isotopic labeling studies reveal strong N-Li contacts in the carboxamide enolate moiety. The method of continuous variations proves deceptive, as octalithiated tetrameric homoaggregates afford hexalithiated trimeric heteroaggregates. A lithium diisopropylamide-lithium enolate mixed aggregate is found to be a C2-symmetric hexalithiated species incorporating two enolate dianions and two lithium diisopropylamide (LDA) subunits. Structural and rate studies show that lithium chloride has little effect on the dynamics of the enolate homoaggregates but forms adducts of unknown structure. Rate studies of alkylations indicate that the aging of the aggregates can have effects spanning orders of magnitude. The LiCl-enolate adduct dramatically accelerates the reaction but requires superstoichiometric quantities owing to putative autoinhibition. Efforts and progress toward eliminating the requisite large excess of LiCl are discussed.
(Ar-tpy)RuII(ACN)3: A Water-Soluble Catalyst for Aldehyde Amidation, Olefin Oxo-Scissoring, and Alkyne Oxygenation
Joarder, Dripta De,Gayen, Subrata,Sarkar, Rajarshi,Bhattacharya, Rajarshi,Roy, Sima,Maiti, Dilip K.
, p. 8468 - 8480 (2019/07/03)
The synthetic chemists always look for developing new catalysts, sustainable catalysis, and their applications in various organic transformations. Herein, we report a new class of water-soluble complexes, (Ar-tpy)RuII(ACN)3, utilizing designed terpyridines possessing electron-donating and -withdrawing aromatic residues for tuning the catalytic activity of the Ru(II) complex. These complexes displayed excellent catalytic activity for several oxidative organic transformations including late-stage C-H functionalization of aldehydes with NH2OR to valuable primary amides in nonconventional aqueous media with excellent yield. Its diverse catalytic power was established for direct oxo-scissoring of a wide range of alkenes to furnish aldehydes and/or ketones in high yield using a low catalyst loading in the water. Its smart catalytic activity under mild conditions was validated for dioxygenation of alkynes to highly demanding labile synthons, 1,2-diketones, and/or acids. This general and sustainable catalysis was successfully employed on sugar-based substrates to obtain the chiral amides, aldehydes, and labile 1,2-diketones. The catalyst is recovered and reused with a moderate turnover. The proposed mechanistic pathway is supported by isolation of the intermediates and their characterization. This multifaceted sustainable catalysis is a unique tool, especially for late-stage functionalization, to furnish the targeted compounds through frequently used amidation and oxygenation processes in the academia and industry.
Copper Catalyzed One-Pot Three-Component Imination-Alkynylation-aza-Michael Sequence: Enantio- And Diastereoselective Syntheses of 1,3-Disubstituted Isoindolines and Tetrahydroisoquinolines
Das, Braja Gopal,Shah, Sadhna,Singh, Vinod K.
supporting information, p. 4981 - 4985 (2019/07/08)
An enantio- and diastereoselective syntheses of 1, 3-disubstituted isoindolines and tetrahydroisoquinolines via CuI-Pybox-diPh catalyzed one-pot imination-alkynylation-aza-Michael sequence has been reported. The three-component reaction produces one C-C and two C-N bonds sequentially with high yield (up to 92%), enantioselectivity (up to 99%), and diastereoselectivity (up to 9:1) in a single operation. Furthermore, the synthetic utility of the product has been demonstrated by LiAlH4 reduction of ester and hydrogenation of alkyne functionality without losing the stereoselectivity.
Efficient Vanadium-Catalyzed Aerobic C?C Bond Oxidative Cleavage of Vicinal Diols
Amadio, Emanuele,González-Fabra, Joan,Carraro, Davide,Denis, William,Gjoka, Blerina,Zonta, Cristiano,Bartik, Kristin,Cavani, Fabrizio,Solmi, Stefania,Bo, Carles,Licini, Giulia
supporting information, p. 3286 - 3296 (2018/05/30)
The aerobic oxidative C?C bond cleavage of vicinal diols catalyzed by vanadium amino triphenolates is described. Our results show that C?C bond cleavage can be performed in different solvents, under an air or oxygen atmosphere, with a large variety of glycols (cyclic or linear, with aromatic or aliphatic substituents) affording the corresponding carbonyl derivatives with high chemoselectivity. Reactions can be performed with as little as 10 ppm of catalyst reaching TON up to 81,000 and TOFs of up to 4150 h?1. A reaction mechanism, rationalized by density functional theory calculations, is also proposed. (Figure presented.).
A de Novo Synthetic Route to 1,2,3,4-Tetrahydroisoquinoline Derivatives
ábrahámi, Renáta A.,Fustero, Santos,Fül?p, Ferenc,Kiss, Loránd
supporting information, p. 2066 - 2070 (2018/03/29)
A novel synthetic approach was developed for the construction of the 1,2,3,4-tetrahydroisoquinoline framework possessing varied functions. The synthetic strategy was based on oxidative ring opening of some indene derivatives through their C=C bond, followed by double reductive amination of the dicarbonyl intermediates with various primary alkyl- or fluoroalkylamines.
Highly efficient biphasic ozonolysis of alkenes using a high-throughput film-shear flow reactor
Kendall, Alexander J.,Barry, Justin T.,Seidenkranz, Daniel T.,Ryerson, Ajay,Hiatt, Colin,Salazar, Chase A.,Bryant, Dillon J.,Tyler, David R.
supporting information, p. 1342 - 1345 (2018/03/27)
A new method for ozonolysis of alkenes using a continuous flow film-shear reactor was developed. The reactor uses a shearing microfluidic mixing chamber to provide biphasic mixing of an organic phase and aqueous phase with ozone gas. The H2O acts as an in situ reducing agent for the carbonyl oxide intermediate, providing ketones and aldehydes directly from the reaction mixture. Flow rates of up to 1.0 mmol/min (alkene) with an ozone reaction efficiency of >70% were achieved. Aryl conjugated olefins reacted to form carbonyl species in good yields on a multi-gram scale; however, alkyl olefins reacted with ozone to predominantly form secondary ozonides. The discrepancy in product distributions between alkyl and aryl olefins likely originates from the electronic stability of the carbonyl oxide intermediate, which is longer lived for aryl derivatives due to conjugation.
Organocatalytic, Enantioselective Synthesis of 1- and 3-Substituted Isochromans via Intramolecular Oxa-Michael Reaction of Alkoxyboronate: Synthesis of (+)-Sonepiprazole
Ravindra, Barnala,Maity, Sanjay,Das, Braja Gopal,Ghorai, Prasanta
, p. 7008 - 7018 (2015/07/28)
The enantioselective oxa-Michael reaction of alkoxyboronate strategy was demonstrated to provide a new and practical route to enantioriched 1- and 3-substituted isochromans using a chiral bifunctional organocatalyst. Furthermore, this methodology was exte
