253426-71-0Relevant academic research and scientific papers
Chiral Alkyl Amine Synthesis via Catalytic Enantioselective Hydroalkylation of Enecarbamates
Qian, Deyun,Bera, Srikrishna,Hu, Xile
supporting information, p. 1959 - 1967 (2021/02/06)
Chiral alkyl amines are omnipresent as bioactive molecules and synthetic intermediates. The catalytic and enantioselective synthesis of alkyl amines from readily accessible precursors is challenging. Here we develop a nickel-catalyzed hydroalkylation method to assemble a wide range of chiral alkyl amines from enecarbamates (N-Cbz-protected enamines) and alkyl halides with high regio- and enantioselectivity. The method works for both nonactivated and activated alkyl halides and is able to produce enantiomerically enriched amines with two minimally differentiated α-alkyl substituents. The mild conditions lead to high functional group tolerance, which is demonstrated in the postproduct functionalization of many natural products and drug molecules, as well as the synthesis of chiral building blocks and key intermediates to bioactive compounds.
Br?nsted Acid-Catalyzed Aza-Ferrier Reaction of N, O-Allenyl Acetals: Synthesis of β-Amino-α-methylene Aldehydes
Tayama, Eiji,Ishikawa, Yuki
supporting information, p. 9405 - 9414 (2020/08/14)
A Tf2NH-catalyzed aza-Ferrier reaction of N,O-allenyl acetals was reported. This protocol provided various types of β-amino-α-methylene aldehydes as the products. The N,O-allenyl acetal substrates were easily prepared by base-induced isomerization of N,O-propargyl acetals with Triton B. The N,O-propargyl acetals were prepared from the corresponding aldehydes or lactams. Further synthetic applications of the products were also described.
Carbonylative C?C Bond Activation of Electron-Poor Cyclopropanes: Rhodium-Catalyzed (3+1+2) Cycloadditions of Cyclopropylamides
Dalling, Andrew G.,Yamauchi, Takayuki,McCreanor, Niall G.,Cox, Lydia,Bower, John F.
supporting information, p. 221 - 225 (2018/12/11)
Rh-catalyzed carbonylative C?C bond activation of cyclopropylamides generates configurationally stable rhodacyclopentanones that engage tethered alkenes in (3+1+2) cycloadditions. These studies provide the first examples of multicomponent cycloadditions t
Photochemical Alkene Isomerization for the Synthesis of Polysubstituted Furans and Pyrroles under Neutral Conditions
Walker, Johannes C. L.,Werrel, Simon,Donohoe, Timothy J.
supporting information, p. 13114 - 13118 (2019/10/22)
A photochemical approach to polysubstituted heterocycles using UV-induced alkene isomerization is described. The method allows for the synthesis of disubstituted furans and pyrroles under mild and neutral conditions and also provides access to a class of trisubstituted furans pertinent to natural-product synthesis. The method has broad functional-group tolerance and many richly decorated heterocycles have been prepared incorporating functional groups that are unstable under Br?nsted and Lewis acidic conditions.
Asymmetric Aminalization via Cation-Binding Catalysis
Park, Sang Yeon,Liu, Yidong,Oh, Joong Suk,Kweon, Yoo Kyung,Jeong, Yong Bok,Duan, Mengying,Tan, Yu,Lee, Ji-Woong,Yan, Hailong,Song, Choong Eui
supporting information, p. 1020 - 1025 (2017/12/15)
Asymmetric cation-binding catalysis, in principle, can generate “chiral” anionic nucleophiles, where the counter cations are coordinated within chiral environments. Nitrogen nucleophiles are intrinsically basic, therefore, its use as nucleophiles is often challenging and limiting the scope of the reaction. Particularly, a formation of configurationally labile aminal centers with alkyl substituents has been a formidable challenge due to the enamine/imine equilibrium of electrophilic substrates. Herein, we report enantioselective nucleophilic addition reactions of potassium phthalimides to Boc-protected alkyl- and aryl-substituted α-amido sulfones. In situ generated imines smoothly reacted with the nitrogen nucleophiles to corresponding aminals with good to excellent enantioselectivitiy under mild reaction conditions. In addition, transformation of aminal products gave biologically relevant pyrrolidinone-fused hexahydropyrimidine scaffold with excellent stereoselectivity and good yield.
Broad Spectrum Enolate Equivalent for Catalytic Chemo-, Diastereo-, and Enantioselective Addition to N-Boc Imines
Trost, Barry M.,Hung, Chao-I
supporting information, p. 15940 - 15946 (2016/01/09)
Alkynyl ketones are attractive but challenging nucleophiles in enolate chemistry. Their susceptibility to other reactions such as Michael additions and the difficulty of controlling the enolate geometry make them difficult substrates. Mannich-type reactions, which previously have not been reported using N-carbamoyl-imines with simple ketone enolates, became our objective. In this report, we describe the first direct catalytic Mannich-type reaction between various ynones and N-Boc imines, whose stereocontrol presumably derives from catalyst control of enolate geometry. This method produces α-substituted β-amino ynones with excellent chemo-, diastereo-, and enantioselectivity. The products can be readily transformed into a broad range of molecular scaffolds upon further one-step transformations, demonstrating the utility of ynones as masked synthetic equivalents for a variety of unsymmetrically substituted acyclic ketones. In particular, alkynyl alkyl ketones resolve the long-standing problem of the inability to use the enolates of unsymmetrical dialkyl ketones lacking α-branching for regio- and stereoselective reactions.
Asymmetric disulfonimide-catalyzed synthesis of δ-amino-β-ketoester derivatives by vinylogous Mukaiyama-Mannich reactions
Wang, Qinggang,Van Gemmeren, Manuel,List, Benjamin
supporting information, p. 13592 - 13595 (2015/01/09)
An organocatalytic asymmetric synthesis of δ-amino-β-ketoester derivatives has been developed. A chiral disulfonimide (DSI) serves as a highly efficient precatalyst for a vinylogous Mukaiyama-Mannich reaction of readily available dioxinone-derived silylox
Asymmetric synthesis of anti -β-amino-α-hydroxy esters via dynamic kinetic resolution of β-amino-α-keto esters
Goodman, C. Guy,Do, Dung T.,Johnson, Jeffrey S.
supporting information, p. 2446 - 2449 (2013/06/27)
A method for the asymmetric synthesis of enantioenriched anti-α-hydroxy-β-amino acid derivatives by enantioconvergent reduction of the corresponding racemic α-keto esters is presented. The requisite α-keto esters are prepared via Mannich addition of ethyl
1,4-Elimination/Br?nsted acid catalyzed aza-Ferrier reaction sequence as an entry to β-amino-β,γ-unsaturated aldehydes
Tayama, Eiji,Horikawa, Kouki,Iwamoto, Hajime,Hasegawa, Eietsu
supporting information, p. 2745 - 2752 (2013/04/10)
The 1,4-elimination reaction of (Z)-N-Boc-2-(4-methoxy-2-alkenyloxy)amines with Br?nsted acids catalyzed aza-Ferrier reaction of the 1,4-eliminated product, thus obtained, afforded various β-amino-β,γ-unsaturated aldehydes. The scope and limitation of thi
Novel bifunctional thiourea-ammonium salt catalysts derived from amino acids: Application to highly enantio- and diastereoselective aza-Henry reaction
Wang, Hong-Yu,Chai, Zhuo,Zhao, Gang
supporting information, p. 5104 - 5111 (2013/06/27)
The development of new efficient and easily accessible catalysts has been one of the focuses in asymmetric phase-transfer catalysis. In this paper, a novel class of chiral bifunctional thiourea-ammonium phase-transfer catalysts were synthesized from commercially available α-amino acids. The structural modularity of these catalysts permits facile tunings to achieve optimum results, which was demonstrated in catalyzing the aza-Henry reaction with excellent enantioselectivities (up to 99.5% ee) and diastereoselectivities (up to >25:1 dr).
