257928-44-2Relevant academic research and scientific papers
Regioselective Copper-Catalyzed Oxidative Coupling of α-Alkylated Styrenes with Tertiary Alkyl Radicals
Wang, Cong,Liu, Rui-Hua,Tian, Ming-Qing,Hu, Xu-Hong,Loh, Teck-Peng
, p. 4032 - 4035 (2018)
A radical-mediated oxidative cross-coupling of readily accessible α-alkylated styrenes with 1,3-dicarbonyl compounds utilizing a combination of Cu(OAc)2 and air as a catalytic system is described. Rather than requiring α-halocarbonyl compounds, this efficient approach enables direct installation of tertiary functionalized alkyl motifs to olefins with simple carbonyl derivatives. The novel protocol is characterized with high allylic selectivities via a competing β-H elimination. Both radical-clock and -trapping experiments provided clear-cut evidence for the intermediacy of an α-keto carbon-centered radical.
Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
Dong, Guangbin,Xu, Yan,Zhou, Xukai
supporting information, p. 20042 - 20048 (2021/12/03)
The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
Rhodium-Catalyzed Intermolecular Cyclopropanation of Benzofurans, Indoles, and Alkenes via Cyclopropene Ring Opening
Jeyaseelan, Rubaishan,Lautens, Mark,Ross, Rachel J.
supporting information, (2020/06/29)
The generation of metal carbenoids via ring opening of cyclopropenes by transition metals offers a simple entry into highly reactive intermediates. Herein, we describe a diastereoselective intermolecular rhodium-catalyzed cyclopropanation of heterocycles and alkenes using cyclopropenes as carbene precursors with a low loading of a commercially available rhodium catalyst. The reported method is scalable and could be performed with catalyst loadings as low as 0.2 mol %, with no impact to the reaction yield or selectivity.
Lewis Acid Catalyzed Transfer Hydromethallylation for the Construction of Quaternary Carbon Centers
Walker, Johannes C. L.,Oestreich, Martin
, p. 15386 - 15389 (2019/10/28)
The design and gram-scale synthesis of a cyclohexa-1,4-diene-based surrogate of isobutene gas is reported. Using the highly electron-deficient Lewis acid B(C6F5)3, application of this surrogate in the hydromethallylation of electron-rich styrene derivatives provided sterically congested quaternary carbon centers. The reaction proceeds by C(sp3)?C(sp3) bond formation at a tertiary carbenium ion that is generated by alkene protonation. The possibility of two concurrent mechanisms is proposed on the basis of mechanistic experiments using a deuterated surrogate.
Piperidine renin inhibitors: from leads to drug candidates
Maerki, H. P.,Binggeli, A.,Bittner, B.,Bohner-Lang, V.,Breu, V.,Bur, D.,Coassolo, Ph.,Clozel, J. P.,D'Arcy, A.,Doebeli, H.,Fischli, W.,et al.
, p. 21 - 28 (2007/10/03)
Non-peptidomimetic renin inhibitors of the piperidine type represent a novel structural class of compounds potentially free of the drawbacks seen with peptidomimetic compounds so far. Synthetic optimization in two structural series focusing on improvement
Process and intermediates for preparation of substituted piperidine-epoxides
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, (2008/06/13)
The present invention concerns intermediates useful in and a process for the preparation of a compound of formula 1 or a salt thereof comprisingepoxidation of a compound of formula 2 or a salt thereof wherein A, R1and R2are as herein
