72316-18-8Relevant articles and documents
Transition-Metal-Free Deaminative Vinylation of Alkylamines
Hu, Jiefeng,Cheng, Bo,Yang, Xianyu,Loh, Teck-Peng
, p. 4902 - 4908 (2019/09/13)
The amino group is one of the most fundamental structural motifs in natural products and synthetic chemicals. However, amines potential as effective alkylating agents in organic synthesis is still problematic. A unified strategy has been established for deaminative vinylation of the alkylamines with vinyl boronic acids by C?N bond activation under catalyst-free conditions. The key to the high reactivity is the utilization of pyridinium salt-activated alkylamines, with a base as a promoter. The transformation exhibits good functional group compatibility, and includes inexpensive primary amine feedstocks and amino acids. The proposed method can serve as a powerful synthetic method for late-stage modification of complex compounds. Mechanistic experiments suggest that free radical processes are involved in this system. (Figure presented.).
Mild Base Promoted Nucleophilic Substitution of Unactivated sp3-Carbon Electrophiles with Alkenylboronic Acids
Liu, Shiwen,Zeng, Xiaojun,Hammond, Gerald B.,Xu, Bo
, p. 3667 - 3671 (2018/09/12)
Diverse alkenylboronic acids react smoothly with various sp3-carbon electrophiles such as unactivated alkyl triflates in the presence of mild bases such as K3PO4. The reaction protocol is very mild and thereby enables high functional group tolerance. This transition metal-free condition is orthogonal towards the classic transition metal catalyzed Suzuki coupling. (Figure presented.).
N-B dative bond-induced [3.3.0] bicyclic boronate-tethered exo-selective intramolecular Diels-Alder reaction
Feng, Chao,Wang, Hong,Xu, Liang,Li, Pengfei
, p. 7136 - 7139 (2015/07/01)
We report herein a highly exo-selective intramolecular Diels-Alder reaction of alkenyl boronates which employs an N-B dative bond-involved bicyclic rigid tether. Complex C(sp3)-rich polycyclic molecules containing up to 8 stereocenters can be readily formed via an operationally simple two-step procedure.
Enantioselective Multicomponent Condensation Reactions of Phenols, Aldehydes, and Boronates Catalyzed by Chiral Biphenols
Barbato, Keith S.,Luan, Yi,Ramella, Daniele,Panek, James S.,Schaus, Scott E.
supporting information, p. 5812 - 5815 (2015/12/11)
Chiral diols and biphenols catalyze the multicomponent condensation reaction of phenols, aldehydes, and alkenyl or aryl boronates. The condensation products are formed in good yields and enantioselectivities. The reaction proceeds via an initial Friedel-Crafts alkylation of the aldehyde and phenol to yield an ortho-quinone methide that undergoes an enantioselective boronate addition. A cyclization pathway was discovered while exploring the scope of the reaction that provides access to chiral 2,4-diaryl chroman products, the core of which is a structural motif found in natural products.
Rhodium(III)-catalyzed cross-coupling of alkenylboronic acids and N -pivaloyloxylamides
Feng, Chao,Loh, Teck-Peng
supporting information, p. 3444 - 3447 (2014/07/21)
Rh(III)-catalyzed umpolung amidation of alkenylboronic acids for the synthesis of enamides is reported. This reaction proceeds readily at room temperature and displays an extremely wide spectrum of functional group tolerance. With cooperation of hydrobora
Anomalies in the stereoselectivity of the petasis reaction using styrenyl boronic acids
Churches, Quentin I.,Johnson, James K.,Fifer, Nathan L.,Hutton, Craig A.
scheme or table, p. 62 - 67 (2011/10/05)
The Petasis three-component coupling reaction of N-benzylphenylglycinol, glyoxylic acid, and styrenylboronic acids allows for the efficient synthesis of functionalized homoarylalanine derivatives. The reactions were shown to proceed in high yield but low selectivity, regardless of the nature of the substituent on the styrenylboronic acid component. Anomalies in the stereoselectivity of these reactions compared with previously reported results have been traced to the source of the organoboronic acid. Asymmetric dihydroxylation of the unsaturated amino acid derivatives enables a highly efficient route to dihydroxyhomoarylalanine derivatives. CSIRO 2011.
Synthesis and biological evaluation of 6,7-disubstituted 4-aminopyrido[2,3-d]pyrimidines as adenosine kinase inhibitors
Perner, Richard J.,Lee, Chih-Hung,Jiang, Meiqun,Gu, Yu-Gui,DiDomenico, Stanley,Bayburt, Erol K.,Alexander, Karen M.,Kohlhaas, Kathy L.,Jarvis, Michael F.,Kowaluk, Elizabeth L.,Bhagwat, Shripad S.
, p. 2803 - 2807 (2007/10/03)
The synthesis and structure-activity relationship of a series of 6,7-disubstituted 4-aminopyrido[2,3-d]pyrimidines as novel non-nucleoside adenosine kinase inhibitors is described. A variety of substituents, primarily aryl, at the C6 and C7 positions of the pyridopyrimidine core were found to yield analogues that are potent inhibitors of adenosine kinase. In contrast to the 5,7-disubstituted and 5,6,7-trisubstituted pyridopyrimidine series, these analogues exhibited only modest potency to inhibit AK in intact cells.
An efficient synthesis of chalcones based on the Suzuki reaction
Eddarir, Said,Cotelle, Nicole,Bakkour, Youssef,Rolando, Christian
, p. 5359 - 5363 (2007/10/03)
A general method for the synthesis of chalcones based on the Suzuki reaction either between cinnamoyl chlorides and phenylboronic acids or between benzoyl chlorides and phenylvinylboronic acids is described.
Vinylborane formation in rhodium-catalyzed hydroboration of vinylarenes. Mechanism versus borane structure and relationship to silation
Brown, John M.,Lloyd-Jones, Guy C.
, p. 866 - 878 (2007/10/02)
Attempted catalytic hydroboration of (4-methoxyphenyl)ethene 1 with R,R-3-isopropyl-4-methyl-5-phenyl-1,3,2-oxazaborolidine 6 proceeded extremely slowly relative to the 3-methyl analog 2 derived from φ-ephedrine when diphosphinerhodium complexes were employed. With phosphine-free rhodium catalysts, especially the 4-methoxy-phenylethene complex 7, the reaction proceeded rapidly and quantitatively to give only the corresponding (E)-vinylborane 9 and 4-methoxyethylbenzene 8 in equimolar amounts. Isotopic labeling and kinetic studies demonstrated that this reaction pathway is initiated by the formation of a rhodium hydride with subsequent reversible and regiospecific H-transfer to the terminal carbon, giving an intermediate which adds the borane and then eliminates the hydrocarbon product. Further migration of the secondary borane fragment from rhodium to the β-carbon of the coordinated olefin occurs, followed by Rh-H β-elimination which produces the vinylborane product and regenerates the initial catalytic species. When the same catalytic reaction is carried out employing catecholborane in place of the oxazaborolidine, an exceedingly rapid turnover occurs. The products are again 4-methoxyethylbenzene and the (E)-vinylborane 23 but accompanied by the primary borane 24 in proportions which vary with the experimental conditions. None of the secondary borane, which is the exclusive product when pure ClRh(PPh3)3 is employed as catalyst, is formed. The product variation as a function of initial reactant concentration was fitted to a model in which the rhodium-borane intermediate in the catalytic cycle undergoes two competing reactions-β-elimination of Rh-H versus addition of a further molecule of catecholborane. The model demonstrates that a kinetic isotope effect of 3.4 operates in the β-elimination step, but none is evident in the addition of catecholborane B-D to rhodium. A similar analysis was successfully applied to the catalytic hydrosilylation of 4-methoxystyrene, with HSiEt3, again employing the phosphine-free rhodium catalyst 7; the product distribution between primary silane 29 and vinylsilane 28 was successfully predicted. The results intimate that silation (i.e., the formation of vinylsilanes under the conditions of catalytic hydrosilylation) can best be explained by a Rh-H based mechanistic model rather than the commonly assumed variant on the Chalk-Harrod catalytic cycle. They provide an explanation for the "oxygen effect" on the rate of Rh-catalyzed hydrosilylations.
