87422-10-4Relevant academic research and scientific papers
Stereoselective Iridium-N,P-Catalyzed Double Hydrogenation of Conjugated Enones to Saturated Alcohols
Andersson, Pher G.,Krajangsri, Suppachai,Peters, Bram B. C.,Zheng, Jia
, (2022/05/20)
Asymmetric hydrogenation of prochiral substrates such as ketones and olefins constitutes an important instrument for the construction of stereogenic centers, and a multitude of catalytic systems have been developed for this purpose. However, due to the different nature of the π-system, the hydrogenation of olefins and ketones is normally catalyzed by different metal complexes. Herein, a study on the effect of additives on the Ir-N,P-catalyzed hydrogenation of enones is described. The combination of benzamide and the development of a reactive catalyst unlocked a novel reactivity mode of Crabtree-type complexes toward C=O bond hydrogenation. The role of benzamide is suggested to extend the lifetime of the dihydridic iridium intermediate, which is prone to undergo irreversible trimerization, deactivating the catalyst. This unique reactivity is then coupled with C=C bond hydrogenation for the facile installation of two contiguous stereogenic centers in high yield and stereoselectivity (up to 99% ee, 99/1 d.r.) resulting in a highly stereoselective reduction of enones.
Kinetic Resolution of Allyltriflamides through a Pd-Catalyzed C-H Functionalization with Allenes: Asymmetric Assembly of Tetrahydropyridines
González, José Manuel,Cendón, Borja,Mascare?as, José Luis,Gulías, Moisés
supporting information, p. 3747 - 3752 (2021/04/06)
Enantioenriched, six-membered azacycles are essential structural motifs in many products of pharmaceutical or agrochemical interest. Here we report a simple and practical method for enantioselective assembly of tetrahydropyridines, which is paired to a ki
Highly Active Cooperative Lewis Acid—Ammonium Salt Catalyst for the Enantioselective Hydroboration of Ketones
Titze, Marvin,Heitk?mper, Juliane,Junge, Thorsten,K?stner, Johannes,Peters, René
, p. 5544 - 5553 (2021/02/05)
Enantiopure secondary alcohols are fundamental high-value synthetic building blocks. One of the most attractive ways to get access to this compound class is the catalytic hydroboration. We describe a new concept for this reaction type that allowed for exceptional catalytic turnover numbers (up to 15 400), which were increased by around 1.5–3 orders of magnitude compared to the most active catalysts previously reported. In our concept an aprotic ammonium halide moiety cooperates with an oxophilic Lewis acid within the same catalyst molecule. Control experiments reveal that both catalytic centers are essential for the observed activity. Kinetic, spectroscopic and computational studies show that the hydride transfer is rate limiting and proceeds via a concerted mechanism, in which hydride at Boron is continuously displaced by iodide, reminiscent to an SN2 reaction. The catalyst, which is accessible in high yields in few steps, was found to be stable during catalysis, readily recyclable and could be reused 10 times still efficiently working.
Capturing the Monomeric (L)CuH in NHC-Capped Cyclodextrin: Cavity-Controlled Chemoselective Hydrosilylation of α,β-Unsaturated Ketones
Bistri-Aslanoff, Olivia,Derat, Etienne,Leloux, Sébastien,Leyssens, Tom,Ménand, Micka?l,Meijide Suárez, Jorge,Riant, Olivier,Roland, Sylvain,Sollogoub, Matthieu,Xu, Guangcan,Zhang, Pinglu,Zhang, Yongmin
supporting information, p. 7591 - 7597 (2020/03/23)
The encapsulation of copper inside a cyclodextrin capped with an N-heterocyclic carbene (ICyD) allowed both to catch the elusive monomeric (L)CuH and a cavity-controlled chemoselective copper-catalyzed hydrosilylation of α,β-unsaturated ketones. Remarkably, (α-ICyD)CuCl promoted the 1,2-addition exclusively, while (β-ICyD)CuCl produced the fully reduced product. The chemoselectivity is controlled by the size of the cavity and weak interactions between the substrate and internal C?H bonds of the cyclodextrin.
Chemoselective Luche-Type Reduction of α,β-Unsaturated Ketones by Magnesium Catalysis
Jang, Yoon Kyung,Magre, Marc,Rueping, Magnus
supporting information, p. 8349 - 8352 (2019/10/16)
The chemoselective reduction of α,β-unsaturated ketones by use of an economic and readily available Mg catalyst has been developed. Excellent yields for a wide range of ketones have been achieved under mild reaction conditions, short times, and low catalyst loadings (0.2-0.5 mol %).
CuH-Catalyzed Enantioselective Ketone Allylation with 1,3-Dienes: Scope, Mechanism, and Applications
Li, Chengxi,Liu, Richard Y.,Jesikiewicz, Luke T.,Yang, Yang,Liu, Peng,Buchwald, Stephen L.
supporting information, p. 5062 - 5070 (2019/03/26)
Chiral tertiary alcohols are important building blocks for the synthesis of pharmaceutical agents and biologically active natural products. The addition of carbon nucleophiles to ketones is the most common approach to tertiary alcohol synthesis but traditionally relies on stoichiometric organometallic reagents that are difficult to prepare, sensitive, and uneconomical. We describe a mild and efficient method for the copper-catalyzed allylation of ketones using widely available 1,3-dienes as allylmetal surrogates. Homoallylic alcohols bearing a wide range of functional groups are obtained in high yield and with good regio-, diastereo-, and enantioselectivity. Mechanistic investigations using density functional theory (DFT) implicate the in situ formation of a rapidly equilibrating mixture of isomeric copper(I) allyl complexes, from which Curtin-Hammett kinetics determine the major isomer of the product. A stereochemical model is provided to explain the high diastereo- and enantioselectivity of this process. Finally, this method was applied to the preparation of an important drug, (R)-procyclidine, and a key intermediate in the synthesis of several pharmaceuticals.
Non-enzymatic acylative kinetic resolution of primary allylic amines
Kolleth, Amandine,Cattoen, Martin,Arseniyadis, Stellios,Cossy, Janine
supporting information, p. 9338 - 9340 (2013/10/01)
A non-enzymatic acetyl transfer-based kinetic resolution of primary allylic amines is reported. The process involves the use of (1S,2S)-1 in conjunction with a supported ammonium salt and affords the corresponding enantio-enriched N-acetylated allylic ami
Highly stereoselective C-C bond formation by rhodium-catalyzed tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor carbenoids and chiral allylic alcohols
Li, Zhanjie,Parr, Brendan T.,Davies, Huw M. L.
supporting information; experimental part, p. 10942 - 10946 (2012/08/07)
The tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor rhodium carbenoids and chiral allyl alcohols is a convergent C-C bond forming process, which generates two vicinal stereogenic centers. Any of the four possible stereoisomers can be selectively synthesized by appropriate combination of the chiral catalyst Rh2(DOSP)4 and the chiral alcohol.
Copper(i) catalyzed asymmetric 1,2-addition of Grignard reagents to α-methyl substituted α,β-unsaturated ketones
Madduri, Ashoka V. R.,Minnaard, Adriaan J.,Harutyunyan, Syuzanna R.
supporting information; scheme or table, p. 1478 - 1480 (2012/02/16)
The first catalytic enantioselective 1,2-addition of Grignard reagents to ketones is presented. This additive-free copper(i) catalyzed 1,2-addition provides chiral allylic tertiary alcohols with an er of up to 98:2 and excellent yields due to the complete shift of overwhelming 1,4-selectivity of copper(i)-catalysts towards 1,2-selectivity in the addition reaction to enones.
CuH-catalyzed enantioselective 1,2-reductions of α,β-unsaturated ketones
Moser, Ralph,Boskovia, Zarko V.,Crowe, Christopher S.,Lipshutz, Bruce H.
supporting information; experimental part, p. 7852 - 7853 (2010/08/04)
The first study on a general technology for arriving at valued nonracemic allylic alcohols using asymmetric ligand-accelerated catalysis by copper hydride is described.
