85908-07-2Relevant academic research and scientific papers
Tailoring Reaction Selectivity by Modulating a Catalytic Diad on a Foldamer Scaffold
Andrews, Mary Katherine,Gellman, Samuel H.,Liu, Xinyu
supporting information, (2022/02/10)
Use of a tunable molecular scaffold to align a reactive diad for bifunctional catalysis can reveal relationships between functional group identity and reactivity that might otherwise be impossible to identify. Here we use an α/β-peptide helix to show that an aligned pair of primary amine groups is uniquely competent to catalyze crossed aldol condensations with an aryl aldehyde as the electrophile. Geometrically similar diads in which one amine group is secondary, or both are secondary, are good catalysts for other types of aldol condensations but not those involving an aryl aldehyde. Catalytic efficacy requires β-amino acid residues that are preorganized for helix formation via cyclic constraint. Conventional peptides (exclusively α-amino acid residues) that display the primary amine diad are poor catalysts, which highlights the critical role of the foldamer scaffold.
Construction of chiral α-tert-amine scaffoldsviaamine-catalyzed asymmetric Mannich reactions of alkyl-substituted ketimines
Homma, Chihiro,Takeshima, Aika,Kano, Taichi,Maruoka, Keiji
, p. 1445 - 1450 (2021/02/12)
Stereoselective Mannich reactions of aldehydes with ketimines provide chiral β-amino aldehydes that bear an α-tert-amine moiety. However, the structural variation of the ketimines is limited due to the formation of inseparableE/Zisomers, low reactivity, and other synthetic difficulties. In this study, a highly diastereodivergent synthesis of hitherto difficult-to-access β-amino aldehydes that bear a chiral α-tert-amine moiety was achieved using the amine-catalyzed Mannich reactions of aldehydes with less-activatedZ-ketimines that bear both alkyl and alkynyl groups.
SELF-CONDENSATION OF ALDEHYDES
-
Paragraph 0021; 0027, (2020/06/05)
An efficient process useful for the self-condensation of aliphatic aldehydes is provided, catalyzed by dialkylammonium carboxylate salts. In particular, the invention provides a facile method for the preparation of 2-ethyl hexenal via the self-condensation of butyraldehyde using various dialkylammonium carboxylates, e.g., diisopropylammonium acetate or dimethylammonium acetate, as catalyst. Additionally, residual nitrogen arising from the catalyst can be reduced to -100 ppm levels in the product via a simple washing procedure. The invention provides a process for preparing alkenals under conditions which limit the formation of undesired impurities and high-boiling oligomeric substances.
Arylation of Aldehydes to Directly Form Ketones via Tandem Nickel Catalysis
Lei, Chuanhu,Zhu, Daoyong,Tangcueco, Vicente Iii Tiu,Zhou, Jianrong Steve
supporting information, p. 5817 - 5822 (2019/08/26)
A nickel-catalyzed arylation of both aliphatic and aromatic aldehydes proceeds with air-stable (hetero)arylboronic acids, with an exceptionally wide substrate scope. The neutral condition tolerates acidic hydrogen and sensitive polar groups and also preserves α-stereocenters of some chiral aldehydes. Interestingly, this nickel(0) catalysis does not follow common 1,2-insertion of arylmetal species to aldehydes and β-hydrogen elimination.
Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
, (2019/05/08)
An intermolecular coupling of primary alcohols and organotriflates has been developed to provide ketones by the action of a Ni(0) catalyst. This oxidative transformation is proposed to occur by the union of three distinct catalytic cycles. Two competitive oxidation processes generate aldehyde in situ via hydrogen transfer oxidation or (pseudo)dehalogenation pathways. As aldehyde forms, a Ni-catalyzed carbonyl-Heck process enables formation of the key carbon-carbon bond. The utility of this rare alcohol to ketone transformation is demonstrated through the synthesis of diverse complex and bioactive molecules.
Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
, p. 6869 - 6874 (2019/05/10)
An intermolecular coupling of primary alcohols and organotriflates has been developed to provide ketones by the action of a Ni(0) catalyst. This oxidative transformation is proposed to occur by the union of three distinct catalytic cycles. Two competitive oxidation processes generate aldehyde in situ via hydrogen transfer oxidation or (pseudo)dehalogenation pathways. As aldehyde forms, a Ni-catalyzed carbonyl-Heck process enables formation of the key carbon-carbon bond. The utility of this rare alcohol to ketone transformation is demonstrated through the synthesis of diverse complex and bioactive molecules.
Rhodium-Catalyzed Synthesis of α,β-Unsaturated Ketones through Sequential C-C Coupling and Redox Isomerization
Li, Hong-Shuang,Guo, Guili,Zhang, Rui-Ze,Li, Fei
, p. 5040 - 5043 (2018/08/24)
A novel Rh(I)-catalyzed sequential C-C coupling and redox isomerization between allylic alcohols and 1,3-dienes has been accomplished. This versatile protocol provides expeditious access to a broad range of polysubstituted α,β-unsaturated ketones with excellent atom economy and regioselectivity.
CONVERSION OF ALCOHOLS TO LINEAR AND BRANCHED FUNCTIONALIZED ALKANES
-
Page/Page column 10-11, (2018/03/09)
Embodiments herein concerns the eco-friendly conversion of simple alcohols to linear or branched functionalized alkanes, by integrated catalysis. The alcohols are firstlyoxidized either chemically or enzymatically to the corresponding aldehydes or ketones, followed by aldol condensations using a catalyst to give the corresponding enals or enones. The enals or enones are subsequently and selectively hydrogenated using a recyclable heterogeneous metal catalyst, organocatalyst or an enzyme to provide linear or branched functionalized alkanes with an aldehyde, keto- or alcohol functionality. The process is also iterative and can be further extended by repeating the above integrated catalysis for producing long-chain functionalized alkanes from simple alcohols.
Structural Characterization and Unique Catalytic Performance of Silyl-Group-Substituted Geminal Dichromiomethane Complexes Stabilized with a Diamine Ligand
Murai, Masahito,Taniguchi, Ryuji,Hosokawa, Naoki,Nishida, Yusuke,Mimachi, Hiroko,Oshiki, Toshiyuki,Takai, Kazuhiko
supporting information, p. 13184 - 13192 (2017/09/26)
Stabilization by a silyl group on the methylene carbon and a diamine ligand led to the isolation of gem-dichromiomethane species. X-ray crystallography confirmed the identity of the structure of this rare example of reactive gem-dimetalloalkane species. T
A comprehensive investigation and optimisation on the proteinogenic amino acid catalysed homo aldol condensation
Ostrowski, Karoline A.,Lichte, Dominik,Stuck, Moritz,Vorholt, Andreas J.
supporting information, p. 592 - 598 (2016/01/15)
A systematic investigation regarding the application of catalytic amounts of all 20 proteinogenic amino acids in the homo aldol condensation of aldehydes is described obtaining excellent yields of the desired α,β-unsaturated aldehyde. These investigations
