131667-57-7Relevant articles and documents
A facile synthesis of cyclic enecarbamates using Dess-Martin periodinane
Yu, Chengzhi,Hu, Longqin
, p. 5167 - 5170 (2001)
A simple and efficient synthesis of cyclic enecarbamates from ω-hydroxycarbamates via tandem oxidative cyclization-dehydration was achieved in 84% to quantitative yield using Dess-Martin periodinane in methylene chloride.
Backbone-Modified C2-Symmetrical Chiral Bisphosphine TMS-QuinoxP*: Asymmetric Borylation of Racemic Allyl Electrophiles
Imamoto, Tsuneo,Ito, Hajime,Iwamoto, Hiroaki,Ozawa, Yu,Takenouchi, Yuta
supporting information, p. 6413 - 6422 (2021/05/31)
A new C2-symmetrical P-chirogenic bisphosphine ligand with silyl substituents on the ligand backbone, (R,R)-5,8-TMS-QuinoxP*, has been developed. This ligand showed higher reactivity and enantioselectivity for the direct enantioconvergent borylation of cy
β-Functionalization of Saturated Aza-Heterocycles Enabled by Organic Photoredox Catalysis
Holmberg-Douglas, Natalie,Choi, Younggi,Aquila, Brian,Huynh, Hoan,Nicewicz, David A.
, p. 3153 - 3158 (2021/04/06)
The direct β-functionalization of saturated aza-heterocycles has remained a synthetic challenge because of the remote and unactivated nature of β-C-H bonds in these motifs. Herein, we demonstrate the β-functionalization of saturated aza-heterocycles enabl
Merging Halogen-Atom Transfer (XAT) and Cobalt Catalysis to Override E2-Selectivity in the Elimination of Alkyl Halides: A Mild Route towardcontra-Thermodynamic Olefins
Zhao, Huaibo,McMillan, Alastair J.,Constantin, Timothée,Mykura, Rory C.,Juliá, Fabio,Leonori, Daniele
supporting information, p. 14806 - 14813 (2021/09/18)
We report here a mechanistically distinct tactic to carry E2-type eliminations on alkyl halides. This strategy exploits the interplay of α-aminoalkyl radical-mediated halogen-atom transfer (XAT) with desaturative cobalt catalysis. The methodology is high-yielding, tolerates many functionalities, and was used to access industrially relevant materials. In contrast to thermal E2 eliminations where unsymmetrical substrates give regioisomeric mixtures, this approach enables, by fine-tuning of the electronic and steric properties of the cobalt catalyst, to obtain high olefin positional selectivity. This unprecedented mechanistic feature has allowed access tocontra-thermodynamic olefins, elusive by E2 eliminations.
Synthesis and Structural Elucidation of 1,2-Disubstituted 3-Fluoropiperidines
Evans, Paul,Fischer, Pauline,Müller-Bunz, Helge,Morris, Morgan
, (2020/02/28)
The work described details the reaction between Selectfluor and a series of 1-carbonyloxy and 1-sulfonyl 2-piperidines in order to generate 3-fluoro-2-methoxypiperidines 3a–f. Their subsequent reaction with allyltrimethylsilane, in the presence of BF3 and TiCl4, is then reported. Studies involving a combination of single-crystal X-ray crystallography and NMR spectroscopy indicate that the allylation process is cis-selective for both carbamate and sulfonamide variants and that optimal levels of diastereoselectivity are obtained using the N-2-nitrobenzene sulfonyl (2-Ns) group. In this manner, the synthesis of a series of 2-allyl 3-fluoro-substituted piperidines (5a, c–f) was achieved. The conversion of both the cis and trans-N-tosyl adducts (5d) into 3-fluorinated analogues of the natural products pelletierine (10) and coniine (11) is subsequently detailed.
?-C(sp2)-H alkylation of enamides using xanthate chemistry
Bertho, Sylvain,Dondasse, Isma?l,Retailleau, Pascal,Nicolas, Cyril,Gillaizeau, Isabelle
supporting information, p. 7129 - 7141 (2020/05/16)
Access to the ?-amino-?,?-unsaturated acyl scaffold was established by applying xanthate chemistry to enamides. This original ?-C(sp2)-H alkylation is regioselective and exhibits broad substrate scope and good functional group tolerance. The la
Electrochemical Scaled-up Synthesis of Cyclic Enecarbamates as Starting Materials for Medicinal Chemistry Relevant Building Bocks
Tereshchenko, Oleksandr D.,Perebiynis, Maryana Y.,Knysh, Irina V.,Vasylets, Olesia V.,Sorochenko, Anna A.,Slobodyanyuk, Eugeniy Y.,Rusanov, Eduard B.,Borysov, Oleksandr V.,Kolotilov, Sergey V.,Ryabukhin, Sergey V.,Volochnyuk, Dmitriy M.
, p. 3229 - 3242 (2020/07/06)
The electrochemical Shono oxidation of Boc-protected cyclic amines was revised. The conditions for scalable electrochemical synthesis of cyclic enecarbamates were found. The developed protocol included recycling of the full range of used reagents, favoring to E-factor reduction according to Green Chemistry requirements. The method opened the way for the convenient preparation of previously uncommon materials, which could become useful synthetic intermediates. Their synthetic potential was evaluated in [2+1] and [2+2] cycloadditions as well as electrophilic functionalization. Moreover, functionalized enecarbamates with carbonyl groups in β-position were used as latent 1,3-bielectrophiles in classical heterocyclizations. In a case of the hydrazine, the corresponding unusually decorated pyrazoles were prepared. The proposed methodology is a straightforward tool for the design and synthesis of Medicinal Chemistry relevant building blocks. As examples, 5-fluoro pipecolic and 3-fluoro isonipecotic acids were synthesized starting from Boc-protected esters of the pipecolic and the isonipecotic acids respectively; the 5-step approach to pyrazole containing α-aminoacids with different linkers between the aminoacidic and pyrazole moieties was elaborated based on the cheapest commercially available racemic and chiral cyclic α-aminoacids; the convenient approach to the functionalized tetrahydropyrido[3,4-d]pyridazines was proposed starting from Boc-protected ester of the isonipecotic acids. (Figure presented.).
Iron-Catalyzed Tunable and Site-Selective Olefin Transposition
Yu, Xiaolong,Zhao, Haonan,Li, Ping,Koh, Ming Joo
supporting information, p. 18223 - 18230 (2020/12/04)
The catalytic isomerization of C-C double bonds is an indispensable chemical transformation used to deliver higher-value analogues and has important utility in the chemical industry. Notwithstanding the advances reported in this field, there is compelling demand for a general catalytic solution that enables precise control of the C═C bond migration position, in both cyclic and acyclic systems, to furnish disubstituted and trisubstituted alkenes. Here, we show that catalytic amounts of an appropriate earth-abundant iron-based complex, a base and a boryl compound, promote efficient and controllable alkene transposition. Mechanistic investigations reveal that these processes likely involve in situ formation of an iron-hydride species which promotes olefin isomerization through sequential olefin insertion/β-hydride elimination. Through this strategy, regiodivergent access to different products from one substrate can be facilitated, isomeric olefin mixtures commonly found in petroleum-derived feedstock can be transformed to a single alkene product, and unsaturated moieties embedded within linear and heterocyclic biologically active entities can be obtained.
Manganese-Catalyzed Desaturation of N-Acyl Amines and Ethers
Li, Gang,Kates, Patrick A.,Dilger, Andrew K.,Cheng, Peter T.,Ewing, William R.,Groves, John T.
, p. 9513 - 9517 (2019/10/14)
Enamines and enol ethers are versatile synthons for chemical synthesis. While several methods have been developed to access such molecules, prefunctionalized starting materials are usually required, and direct desaturation methods remain rare. Herein, we report direct desaturation reactions of N-protected cyclic amines and cyclic ethers using a mild I(III) oxidant, PhI(OAc)2, and an electron-deficient manganese pentafluorophenylporphyrin catalyst, Mn(TPFPP)Cl. This system displays high efficiency for α,β-desaturation of various cyclic amines and ethers. Mechanistic probes suggest that the desaturation reaction occurs via an initial α-C-H hydroxylation pathway, which serves to protect the product from overoxidation.
Normal Alpha Olefin Synthesis Using Dehydroformylation or Dehydroxymethylation
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Paragraph 0127; 0128; 0129, (2019/09/06)
The present invention discloses processes for producing normal alpha olefins, such as 1-hexene, 1-octene, 1-decene, and 1-dodecene in a multistep synthesis scheme from another normal alpha olefin. Also disclosed are reactions for converting aldehydes, primary alcohols, and terminal vicinal diols into normal alpha olefins.
