59336-59-3Relevant academic research and scientific papers
Catalyst control in positional-selective C-H alkenylation of isoxazoles and a ruthenium-mediated assembly of trisubstituted pyrroles
Kumar, Pravin,Kapur, Manmohan
supporting information, p. 2134 - 2138 (2019/03/26)
High levels of catalyst control are demonstrated in determining the positional selectivity in C-H alkenylation of isoxazoles. A cationic rhodium-mediated, strong-directing group promotes C(sp2)-H activation at the proximal aryl ring whereas, the palladium-mediated electrophilic metallation leads to the C(sp2)-H activation at the distal position of the directing group. Synthetic elaboration of this C-H alkenylation product via ruthenium and copper co-catalysis leads to an efficient method for the assembly of densely substituted pyrroles.
Formal Aniline Synthesis from Phenols through Deoxygenative N-Centered Radical Substitution
Lardy, Samuel W.,Luong, Kristine C.,Schmidt, Valerie A.
supporting information, p. 15267 - 15271 (2019/12/11)
Phenolic, lignin-derived substrates have emerged as desirable biorenewable chemical feedstocks for coupling reactions. A radical-mediated conversion of phenol derivatives to anilines is reported, using unfunctionalized hydroxamic acids as the N-centered radical source. The applicability of this triethyl phosphite mediated O-atom transfer approach, which tolerates a range of steric and electronic demands to naturally occurring phenols and lignin models, has been demonstrated in this work to access the corresponding aniline derivatives.
Facile One-Pot Transformation of Primary Alcohols into 3-Aryl- and 3-Alkyl-isoxazoles and -pyrazoles
Kobayashi, Eiji,Togo, Hideo
, p. 3723 - 3735 (2019/09/30)
Various primary alcohols were smoothly transformed into 3-aryl- and 3-alkylisoxazoles in good yields in one pot by successive treatment with PhI(OAc) 2 in the presence of TEMPO, NH 2 OH, and then NCS, followed by reaction with alkynes in the presence of Et 3 N. Similarly, various primary alcohols were smoothly transformed into 3-aryl- and 3-alkylpyrazoles in good yields in one pot by successive treatment with PhI(OAc) 2 in the presence of TEMPO, PhNHNH 2, and then NCS and decyl methyl sulfide, followed by reaction with alkynes in the presence of Et 3 N. Thus, both 3-aryl- and 3-alkylisoxazoles, and 3-aryl- and 3-alkylpyrazoles could be prepared from readily available primary alcohols in one pot under transition-metal-free conditions.
Synthesis of Nitriles from Primary Amides or Aldoximes under Conditions of a Catalytic Swern Oxidation
Ding, Rui,Liu, Yongguo,Han, Mengru,Jiao, Wenyi,Li, Jiaqi,Tian, Hongyu,Sun, Baoguo
, p. 12939 - 12944 (2018/10/20)
The preparation of nitriles from primary amides or aldoximes was achieved by using oxalyl chloride with a catalytic amount of dimethyl sulfoxide in the presence of Et3N. The reactions were complete within 1 h after addition at room temperature. A diverse range of cyano compounds were obtained in good to excellent yields, including aromatic, heteroaromatic, cyclic, and acyclic aliphatic species.
Selective and facile synthesis of α,β-unsaturated nitriles and amides with N-hydroxyphthalimide as the nitrogen source
Yan, Yiyan,Xu, Xiaohe,Jie, Xiaokang,Cheng, Jingya,Bai, Renren,Shuai, Qi,Xie, Yuanyuan
, p. 2793 - 2796 (2018/06/25)
The direct conversion of α,β-unsaturated aldehydes to corresponding nitriles promoted by Pd(OAc)2 and phthalic acid which was hydrolyzed from N-hydroxyphthalimide (NHPI) has been disclosed. Additionally, it was found that when water was used as the solvent, α,β-unsaturated amides was obtained as the main products in good to excellent yields. It was first reported that NHPI was utilized as the nitrogen source to synthesize α,β-unsaturated nitriles and amides from aldehydes. Control experiment demonstrated that aldehydes undergo a process of oximation and dehydration to form nitriles and amides.
Poly(ethylene glycol)–bound sulfonyl chloride as an efficient catalyst for transformation of aldoximes to nitriles
Zhang, Xiao-Lan,Liu, Xiao-Ling,Sang, Xiao-Yan,Sheng, Shou-Ri
, p. 232 - 237 (2017/01/22)
An operationally simple, efficient, and environmentally benign preparation of nitriles in good to excellent yields from various aldoximes in the presence of recyclable poly(ethylene glycol)–bound sulfonyl chloride is described.
Catalytic Enantioselective [3 + 2] Cycloaddition of α-Keto Ester Enolates and Nitrile Oxides
Bartlett, Samuel L.,Sohtome, Yoshihiro,Hashizume, Daisuke,White, Peter S.,Sawamura, Miki,Johnson, Jeffrey S.,Sodeoka, Mikiko
supporting information, p. 8661 - 8666 (2017/07/06)
An enantioselective [3 + 2] cycloaddition reaction between nitrile oxides and transiently generated enolates of α-keto esters has been developed. The catalyst system was found to be compatible with in situ nitrile oxide-generation conditions. A versatile array of nitrile oxides and α-keto esters could participate in the cycloaddition, providing novel 5-hydroxy-2-isoxazolines in high chemical yield with high levels of diastereo- and enantioselectivity. Notably, the optimal reaction conditions circumvented concurrent reactions via O-imidoylation and hetero-[3 + 2] pathways.
Iron-Catalyzed Asymmetric Nitro-Mannich Reaction
Dudek, Agata,Mlynarski, Jacek
, p. 11218 - 11224 (2017/10/27)
The first enantioselective addition of nitroalkanes to imines (nitro-Mannich reaction), mediated by an iron(II) catalyst assembled by a hindered hydroxyethyl-pybox ligand, is described. This valuable carbon-carbon bond-forming reaction proceeds smoothly at room temperature to afford enantioenriched β-nitro amines in good yields and high enantioselectivity, up to 98% with unprecedentedly low iron catalyst loading (5 mol %).
An efficient catalyst-free one-pot synthesis of primary amides from the aldehydes of the Baylis-Hillman reaction
Narendar Reddy, Thatikonda,Raktani, Bikshapathi,Perla, Ramesh,Ravinder, Mettu,Vaidya, Jayathirtha Rao,Babu, N. Jagadeesh
, p. 9203 - 9209 (2017/08/29)
Herein, a facile and efficient method for the preparation of allyl amides from the aldehyde of Baylis-Hillman adducts has been developed using a hydroxylamine/methanol system under a catalyst-free condition. The effects of solvents and temperature on the reaction and substituents on the phenyl ring have been examined. This method is best demonstrated by its advantages such as operational simplicity, moderate to excellent yields, short reaction time, and simple reaction procedure. Most importantly, the reaction proceeds smoothly in the absence of a catalyst and an external oxidant.
Water-Assisted Nitrile Oxide Cycloadditions: Synthesis of Isoxazoles and Stereoselective Syntheses of Isoxazolines and 1,2,4-Oxadiazoles
Kesornpun, Chatchai,Aree, Thammarat,Mahidol, Chulabhorn,Ruchirawat, Somsak,Kittakoop, Prasat
supporting information, p. 3997 - 4001 (2016/03/19)
Conventional methods generate nitrile oxides from oxime halides in organic solvents under basic conditions. However, the present work revealed that water-assisted generation of nitrile oxides proceeds under mild acidic conditions (pH 4-5). Cycloadditions of nitrile oxides with alkynes and alkenes easily occurred in water without using catalysts, thus yielding isoxazoles and isoxazolines, respectively, with excellent stereoselectivity toward five- and six-membered cyclic alkenes. A double stereoselective cycloaddition of two units of a nitrile oxide with cyclohexene was also achieved, thus yielding 1,2,4-oxadiazole derivatives having a unique hybrid isoxazoline-oxadiazole skeleton. Enantiomerically pure isoxazolines were prepared from monoterpenes with a ring strain. In one case, the isoxazoline with a butterfly-like structure was simply prepared, and it might be used as a ligand in asymmetric catalysis.
