2436-29-5Relevant academic research and scientific papers
Exploring endoperoxides as a new entry for the synthesis of branched azasugars
Domeyer, Svenja,Bjerregaard, Mark,Johansson, Henrik,Pedersen, Daniel Sejer
, p. 644 - 647 (2017)
A new class of nitrogen-containing endoperoxides were synthesised by a photochemical [4 + 2]-cycloaddition between a diene and singlet oxygen. The endoperoxides were dihydroxylated and protected to provide a series of endoperoxide building blocks for organic synthesis, with potential use as precursors for the synthesis of branched azasugars. Preliminary exploration of the chemistry of these building blocks provided access to a variety of derivatives including tetrahydrofurans, epoxides and protected amino-tetraols.
Divergent Stereocontrolled Synthesis of the Enantiopure Tetracyclic Cores of Asparagamine A and Stemofoline via an Intramolecular 2-Propylidine-1,3-(bis)silane Bicyclization
Anderson, Bryon K.,Livinghouse, Tom
, p. 9847 - 9855 (2015)
A concise and highly diastereoselective synthesis of the polyfused tetracyclic cores of the Stemona alkaloids asparagamine A and stemofoline that relies on a 2-propylidine-1,3-(bis)silane bicyclization onto a enantiodefined pyrrolidine 2,5-di(cation) equivalent derived from l-malic acid is reported. A crucial feature of this divergent synthetic approach involves the solvolysis of a transient and highly labile tertiary-propargylic hydroxylactam trifluoroacetate in the strongly ionizing medium 5 M LiClO4/Et2O. The acyliminium ion generated in this manner undergoes stereospecific interception by the aforementioned (bis)silane nucleophile.
Robust synthesis and crystal-structure analysis of 7-cyano-7-deazaguanine (PreQ0 base) and 7-(aminomethyl)-7-deazaguanine (PreQ1 base)
Klepper, Florian,Polborn, Kurt,Carell, Thomas
, p. 2610 - 2616 (2005)
We describe robust and efficient synthetic methods for the synthesis of the preQ0 and preQ1 bases, which are the biosynthetic precursors of the hypermodified RNA nucleoside queuosine. The X-ray crystal-structure analysis of preQ1 is also described.
Radical Carbonyl Umpolung Arylation via Dual Nickel Catalysis
Huang, Huan-Ming,Bellotti, Peter,Erchinger, Johannes E.,Paulisch, Tiffany O.,Glorius, Frank
supporting information, p. 1899 - 1909 (2022/02/01)
The formation of carbon-carbon bonds lies at the heart of synthetic organic chemistry and is widely applied to construct complex drugs, polymers, and materials. Despite its importance, catalytic carbonyl arylation remains comparatively underdeveloped, due
Synthesis process of spermidine and intermediate thereof
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Paragraph 0027-0029, (2021/10/27)
The invention provides a synthesis process of spermidine (I) which takes 3 -t-butyloxycarbonyl V (N -) and -1-t-butyloxycarbonyl 4 - IV butanediamine (N -) as a raw material to obtain the spermidine trihydrochloride (-4 - II III) by reductive amination reaction, and provides a novel method for chemical synthesis of spermidine by liberation of the protecting group from the intermediate I (3 -) to obtain the spermidine (III) II.
Cross-Selective Aza-Pinacol Coupling via Atom Transfer Catalysis
Nagib, David A.,Rafferty, Sean M.,Rutherford, Joy E.,Wang, Lu,Zhang, Lumin
supporting information, p. 5622 - 5628 (2021/05/07)
A cross-selective aza-pinacol coupling of aldehydes and imines has been developed to afford valuable β-amino alcohols. This strategy enables chemoselective conversion of aliphatic aldehydes to ketyl radicals, in the presence of more easily reduced imines and other functional groups. Upon carbonyl-specific activation by AcI, a photoinitiated Mn catalyst selectively reduces the resulting α-oxy iodide by an atom transfer mechanism. The ensuing ketyl radical selectively couples to imines, precluding homodimerization by a classical reductive approach. In this first example of reductive, ketyl coupling by atom transfer catalysis, Zn serves as a terminal reductant to facilitate Mn catalyst turnover. This new strategy also enables ketyl radical couplings to alkenes, alkynes, aldehydes, propellanes, and chiral imines.
Organocatalytic diastereo- And enantioselective oxa-hetero-Diels-Alder reactions of enones with aryl trifluoromethyl ketones for the synthesis of trifluoromethyl-substituted tetrahydropyrans
Pasha, Maira,Tanaka, Fujie
supporting information, p. 9242 - 9250 (2021/11/16)
Tetrahydropyran derivatives are found in bioactives, and introduction of the trifluoromethyl group into molecules often improves biofunctions. Here we report diastereo- and enantioselective oxa-hetero-Diels-Alder reactions catalyzed by amine-based catalyst systems that afford trifluoromethyl-substituted tetrahydropyranones. Catalyst systems and conditions suitable for the reactions to provide the desired diastereomer products with high enantioselectivities were identified, and various trifluoromethyl-substituted tetrahydropyranones were synthesized with high diastereo- and enantioselectivities. Mechanistic investigation suggested that the reactions involve a [4 + 2] cycloaddition pathway, in which the enamine of the enone acts as the diene and the ketone carbonyl group of the aryl trifluoromethyl ketone acts as the dienophile. In this study, tetrahydropyran derivatives with the desired stereochemistry that are difficult to synthesize by previously reported methods were concisely obtained, and the range of tetrahydropyran derivatives that can be synthesized was expanded. This journal is
Binuclear Pd(I)-Pd(I) Catalysis Assisted by Iodide Ligands for Selective Hydroformylation of Alkenes and Alkynes
Zhang, Yang,Torker, Sebastian,Sigrist, Michel,Bregovi?, Nikola,Dydio, Pawe?
supporting information, p. 18251 - 18265 (2020/11/02)
Since its discovery in 1938, hydroformylation has been thoroughly investigated and broadly applied in industry (>107 metric ton yearly). However, the ability to precisely control its regioselectivity with well-established Rh- or Co-catalysts has thus far proven elusive, thereby limiting access to many synthetically valuable aldehydes. Pd-catalysts represent an appealing alternative, yet their use remains sparse due to undesired side-processes. Here, we report a highly selective and exceptionally active catalyst system that is driven by a novel activation strategy and features a unique Pd(I)-Pd(I) mechanism, involving an iodide-assisted binuclear step to release the product. This method enables β-selective hydroformylation of a large range of alkenes and alkynes, including sensitive starting materials. Its utility is demonstrated in the synthesis of antiobesity drug Rimonabant and anti-HIV agent PNU-32945. In a broader context, the new mechanistic understanding enables the development of other carbonylation reactions of high importance to chemical industry.
Experimental and computational evidence on gold-catalyzed regioselective hydration of phthalimido-protected propargylamines: An entry to β-amino ketones
Arcadi, Antonio,Aschi, Massimiliano,Marsicano, Vincenzo,Michelet, Véronique
, p. 9438 - 9447 (2020/12/15)
The results of our investigations on the Au-catalyzed regioselective hydration reaction of both alkyl- A nd aryl-substituted N-propargyl phthalimides directed to the selective formation of the corresponding β-phthalimido ketones are described. Experimental data, in particular the observed regioselectivity, have been qualitatively supported by quantum-chemical calculations carried out on model systems in the framework of Density Functional Theory (DFT) followed by quantum theory of atoms in molecules (QTAIMS). Our results suggest that the electronic features of the initial adduct between the propargyl triple bond and the Au(i) catalyst, in particular the character of the gold-triple bond interaction, are essential for the observed regioselectivity. Other effects, such as the presence of the solvent and the formation of a H-bond between the water molecule and the phthalimido moiety, although apparently irrelevant for the regioselectivity, have proven to be kinetically and catalytically rather important. This journal is
Organocatalyzed Aerobic Oxidation of Aldehydes to Acids
Dai, Peng-Fei,Qu, Jian-Ping,Kang, Yan-Biao
supporting information, p. 1393 - 1396 (2019/02/26)
The first example organocatalyzed aerobic oxidation of aldehydes to carboxylic acids in both organic solvent and water under mild conditions is developed. As low as 5 mol % N-hydroxyphthalimide was used as the organocatalyst, and molecular O2 was used as the sole oxidant. No transition metals or hazardous oxidants or cocatalysts were involved. A wide range of carboxylic acids bearing diverse functional groups were obtained from aldehydes, even from alcohols, in high yields.
