338731-71-8Relevant academic research and scientific papers
A new type of L-Tertiary leucine-derived ligand: Synthesis and application in Cu(II)-catalyzed asymmetric Henry reactions
Cai, Zedong,Lan, Ting,Ma, Pengfei,Zhang, Jingfang,Yang, Qingqing,He, Wei
, (2019/08/08)
A new series of Schiff bases derived from amino acids were developed as chiral ligands for Cu(II)-catalyzed asymmetric Henry reactions. The optimum ligand 7d exhibited outstanding catalytic efficiency in the Cu(II)-catalyzed asymmetric Henry additions of four nitroalkanes to different kinds of aldehydes to produce 76 desired adducts in high yields (up to 96%) with excellent enantioselectivities, up to 99% enantiomeric excess (ee).
Asymmetric Synthesis of Carbocyclic Propellanes
Schneider, Lisa M.,Schmiedel, Volker M.,Pecchioli, Tommaso,Lentz, Dieter,Merten, Christian,Christmann, Mathias
, p. 2310 - 2313 (2017/05/12)
A modular synthesis of functionalized carbocyclic propellanes was developed. Formation of the first of two quaternary bridgehead centers has been achieved by desymmetrization of prostereogenic ketones by either Hajos-Parrish-Eder-Sauer-Wiechert-type processes or Werner’s catalytic asymmetric Wittig reaction. The obtained bicyclic enones were subjected to conjugate additions upon which the remaining ring was formed by olefin metathesis. All bridges are amenable to further derivatization, which renders those compounds useful as central units in fragment-based drug discovery or as ligand scaffolds.
A kind of T-leucine derivative of the chiral amine compound and its preparation method and application
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Paragraph 0046-0048; 0052; 0053, (2017/01/26)
The invention discloses a tertiary leucine derived chiral amine compound as well as a preparation method and application thereof. The chiral amine compound contains a tert-butyl group, a primary amine, a secondary amine or a tertiary amine functional group and has the structural formula as shown in the specification; and chiral amine and salts thereof are prepared through simple preparation steps by taking common tert-leucine as the raw material to form the chiral amine compound. The chiral amine and the salts thereof can be used for the asymmetrical Michael additive reaction between alpha, beta-unsaturated ketone and a nucleophilic reagent such as nitrocarbol, malonic ester, substituted oxazolone and the like and the asymmetrical cascade reaction between the alpha, beta-unsaturated ketone and fifth-position unsaturated rhodanine, between fifth-position unsaturated hydantoin and the alpha, beta-unsaturated ketone; and the tertiary leucine derived chiral amine compound has very high catalytic activity and stereoselectivity as well as the highest diastereoselectivity of 30/1 and the highest enantioselectivity of 99%, and is wide in oligomer range.
Enantioselective Synthesis of Dialkylated α-Hydroxy Carboxylic Acids through Asymmetric Phase-Transfer Catalysis
Duan, Shaobo,Li, Sanliang,Ye, Xinyi,Du, Nuan-Nuan,Tan, Choon-Hong,Jiang, Zhiyong
supporting information, p. 7770 - 7778 (2015/08/18)
In the presence of an L-tert-leucine-derived urea-ammonium salt as phase-transfer catalyst, a highly enantioselective alkylation of 5H-oxazol-4-ones with various benzyl bromides and allylic bromides has been developed to furnish catalytic asymmetric synthesis of biologically important dialkylated α-hydroxy carboxylic acids with a broad scope. This is the first example of an L-amino acid-derived urea-ammonium salt being used as a phase-transfer catalyst with excellent catalytic efficiency.
Enantioselective construction of tetrasubstituted stereogenic carbons through bronsted base catalyzed michael reactions: α′-hydroxy enones as key enoate equivalent
Badiola, Eider,Fiser, Bla,Gmez-Bengoa, Enrique,Mielgo, Antonia,Olaizola, Iurre,Urruzuno, Iaki,Garca, Jess M.,Odriozola, Jos M.,Razkin, Jess,Oiarbide, Mikel,Palomo, Claudio
supporting information, p. 17869 - 17881 (2015/02/19)
Catalytic and asymmetric Michael reactions constitute very powerful tools for the construction of new C-C bonds in synthesis, but most of the reports claiming high selectivity are limited to some specific combinations of nucleophile/electrophile compound types, and only few successful methods deal with the generation of all-carbon quaternary stereocenters. A contribution to solve this gap is presented here based on chiral bifunctional Bronsted base (BB) catalysis and the use of α′-oxy enones as enabling Michael acceptors with ambivalent H-bond acceptor/donor character, a yet unreported design element for bidentate enoate equivalents. It is found that the Michael addition of a range of enolizable carbonyl compounds that have previously demonstrated challenging (i.e., α-substituted 2-oxindoles, cyanoesters, oxazolones, thiazolones, and azlactones) to α′-oxy enones can afford the corresponding tetrasubstituted carbon stereocenters in high diastereo- and enantioselectivity in the presence of standard BB catalysts. Experiments show that the α′-oxy ketone moiety plays a key role in the above realizations, as parallel reactions under identical conditions but using the parent α,β-unsaturated ketones or esters instead proceed sluggish and/or with poor stereoselectivity. A series of trivial chemical manipulations of the ketol moiety in adducts can produce the corresponding carboxy, aldehyde, and ketone compounds under very mild conditions, giving access to a variety of enantioenriched densely functionalized building blocks containing a fully substituted carbon stereocenter. A computational investigation to rationalize the mode of substrate activation and the reaction stereochemistry is also provided, and the proposed models are compared with related systems in the literature.
Enantioselective synthesis of coumarins catalyzed by a bifunctional amine-thiourea catalyst
Gao, Yaojun,Ren, Qiao,Wang, Lei,Wang, Jian
supporting information; experimental part, p. 13068 - 13071 (2011/02/21)
Efficient excess: An efficient and facile enantioselective Michael addition reaction through hydrogen-bonding catalysis for the synthesis of coumarin complexes has been developed (see scheme). A simple bifunctional amine-thiourea small molecule has been discovered to catalyze this process with high yields and high to excellent enantiomeric excesses.
Stereoselective reactions. XXXIIII. Design and synthesis of chiral bidentate amines having a bulky group on the chiral carbon.
Toriyama,Tokutake,Koga
, p. 330 - 334 (2007/10/03)
Based on the solution structures of chiral bidentate lithium amides ((R)-3a,b) having a phenyl group on the chiral carbon, chiral bidentate amines ((R)-5a,b-8a,b and (S)-9a,b) having a bulkier group instead of a phenyl group on the chiral carbon were designed and synthesized.
