52853-55-1Relevant academic research and scientific papers
Enantioselective Reductive Divinylation of Unactivated Alkenes by Nickel-Catalyzed Cyclization Coupling Reaction
Peng, Xuejing,Qiao, Jin-Bao,Shu, Xing-Zhong,Yao, Qi-Wei,Zhang, Ya-Qian,Zhao, Zhen-Zhen
supporting information, p. 12961 - 12967 (2021/09/03)
Catalytic asymmetric dicarbofunctionalization of tethered alkenes has emerged as a promising tool for producing chiral cyclic molecules; however, it typically relies on aryl-tethered alkenes to form benzene-fused compounds. Herein, we report an enantioselective cross-electrophile divinylation reaction of nonaromatic substrates, 2-bromo-1,6-dienes. The approach thus offers a route to new chiral cyclic architectures, which are key structural motifs found in various biologically active compounds. The reaction proceeds under mild conditions, and the use of chiral t-Bu-pmrox and 3,5-difluoro-pyrox ligands resulted in the formation of divinylated products with high chemo-, regio-, and enantioselectivity. The method is applicable for the incorporation of chiral hetero- and carbocycles into complex molecules.
Electro-Mechanochemical Atom Transfer Radical Cyclizations using Piezoelectric BaTiO3
Bolm, Carsten,Hernández, José G.,Schumacher, Christian
supporting information, p. 16357 - 16360 (2020/07/13)
The formation and regeneration of active CuI species is a fundamental mechanistic step in copper-catalyzed atom transfer radical cyclizations (ATRC). Typically, the presence of the catalytically active CuI species in the reaction mix
A Simple, Broad-Scope Nickel(0) Precatalyst System for the Direct Amination of Allyl Alcohols
Sweeney, Joseph B.,Ball, Anthony K.,Lawrence, Philippa A.,Sinclair, Mackenzie C.,Smith, Luke J.
supporting information, p. 10202 - 10206 (2018/08/06)
The preparation of allylic amines is traditionally accomplished by reactions of amines with reactive electrophiles, such as allylic halides, sulfonates, or oxyphosphonium species; such methods involve hazardous reagents, generate stoichiometric waste streams, and often suffer from side reactions (such as overalkylation). We report here the first broad-scope nickel-catalysed direct amination of allyl alcohols: An inexpensive NiII/Zn couple enables the allylation of primary, secondary, and electron-deficient amines without the need for glove-box techniques. Under mild conditions, primary and secondary aliphatic amines react smoothly with a range of allyl alcohols, giving secondary and tertiary amines efficiently. This “totally catalytic” method can also be applied to electron-deficient nitrogen nucleophiles; the practicality of the process was demonstrated in an efficient, gram-scale preparation of the calcium antagonist drug substance flunarizine (Sibelium).
Synthesis of Cyclic Guanidines Bearing N-Arylsulfonyl and N-Cyano Protecting Groups via Pd-Catalyzed Alkene Carboamination Reactions
Peterson, Luke J.,Luo, Jingyi,Wolfe, John P.
supporting information, p. 2817 - 2820 (2017/06/07)
Palladium-catalyzed carboamination reactions of N-allylguanidines bearing cleavable N-cyano or N-arylsulfonyl protecting groups are described. The reactions afford cyclic guanidine products in good yield, and transformations of substrates bearing internal alkenes proceed with high diastereoselectivity. Deuterium labeling studies indicate these transformations proceed via anti-aminopalladation pathways.
Cycloamidination of Aminoalkenes with Nitriles: Synthesis of Substituted 2-Imidazolines and Tetrahydropyrimidines
Huang, Shujian,Shao, Yinlin,Zhang, Lixin,Zhou, Xigeng
supporting information, p. 14452 - 14456 (2016/01/25)
The first catalytic cycloamidination of aminoalkenes with nitriles has been achieved by using rare-earth complexes. This reaction is equivalent to the desired intramolecular hydroamination of alkenylamidines, and allows a new direct access to substituted 2-imidazolines and tetrahydropyrimidines in high yields under operationally simple reaction conditions. Moreover, the methodology is also efficient for synthesis of symmetric and unsymmetric bridged diimidazolines. Compared with the traditional stepwise-mediated synthetic approaches, the present method avoids the use of additives and harsh reaction conditions, and thus leads to a completely different product distribution. Mechanistic data suggest that the reaction involves the initial NH activation by lanthanide complex followed by nitrile insertion into a Ln-N bond to form an amidinate lanthanide intermediate which undergoes the cyclization.
Simple, chemoselective, catalytic olefin isomerization
Crossley, Steven W. M.,Barabé, Francis,Shenvi, Ryan A.
supporting information, p. 16788 - 16791 (2015/01/09)
Catalytic amounts of Co(SaltBu,tBu)Cl and organosilane irreversibly isomerize terminal alkenes by one position. The same catalysts effect cycloisomerization of dienes and retrocycloisomerization of strained rings. Strong Lewis bases like amines and imidazoles, and labile functionalities like epoxides, are tolerated.
Ring-closing metathesis of vinyl fluorides towards α-fluorinated α,β-unsaturated lactams and lactones
Marhold, Michael,Stillig, Christian,Fr?hlich, Roland,Haufe, Günter
supporting information, p. 5777 - 5785 (2014/10/15)
Ring-closing olefin metathesis reactions (RCM) using Grubbs II or Hoveyda's catalysts have been applied to a series of N-alkenyl-N-benzyl-α-fluoroacrylamides. α-Fluoro-α,β-unsaturated γ- or δ-lactams incorporating a fluorinated double bond were obtained in moderate to good yields, depending on the nature of substituents on the benzyl ring. The corresponding seven- and eight-membered lactams were not formed under similar conditions. When the N-benzyl group was replaced by an N-tosyl group, the corresponding ε-lactam was also formed in 38% yield. When N-(2-fluoroallyl) derivatives were used instead of fluoroacryloyl derivatives, six-, seven-, and eight-membered N-heterocycles were obtained in low yields. This method was also used to synthesize fluorinated α,β-unsaturated analogues of pyrrolizidine and indolizidine alkaloids from prolinol, and also to synthesize N-benzyl-3-fluoroquinolone in three steps from commercially available 2-vinylaniline in 44% overall yield. Also 3-fluorocoumarin and 3-fluorochromene were prepared from ovinylphenol, and 3-fluoro-benzoxepine was available from o-allylphenol.
THIAZOLOPYRIDINONE DERIVATES AS MCH RECEPTOR ANTAGONISTS
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Page/Page column 127, (2008/06/13)
The present invention relates to a melanin concentrating hormone antagonist compound of formula (I); wherein w, R1, q, p, R2, t, Ar1, L1, R3 and R4 are as defined, or a pharmaceutically acceptable salt, solvate, or enantiomer thereof useful in the treatment, prevention or amelioration of symptoms associated with obesity and related diseases.
Transition Metal-Catalyzed Radical Cyclizations: A Low-Temperature Process for the Cyclization of N-Protected N-Allyltrichloroacetamides to Trichlorinated γ-Lactams and Application to the Stereoselective Preparation of β,γ-Disubstituted γ-Lactams
Nagashima, Hideo,Ozaki, Nobuyasu,Ishii, Masayuki,Seki, Koji,Washiyama, Masayoshi,Itoh, Kenji
, p. 464 - 470 (2007/10/02)
Cyclisations of N-substituted N-allyltrichloroacetamides, where the substituent is an alkyl, Cbz, Boc, Ts, or Ms group, are catalyzed by a 1:1 mixture of CuCl and bipyridine to give the corresponding β,γ-trichlorinated γ-lactams in high yields.The reactions proceed at temperatures from -78 deg C to room temperature.Cyclizations of N-allyltrichloroacetamides of acyclic secondary allylic amines are achieved with good selectivity; the cis/trans ratios of the γ-lactams formed were dependent on the substituents on the nitrogen atom.The stereochemical outcome is compared with that of free-radical cyclization.
