877150-02-2Relevant academic research and scientific papers
Tunable System for Electrochemical Reduction of Ketones and Phthalimides
Chen, Gong,Qiao, Tianjiao,Wang, Yaxin,Zhang, Jian,Zhao, Jianyou
, p. 3297 - 3302 (2021/10/14)
Herein, we report an efficient, tunable system for electrochemical reduction of ketones and phthalimides at room temperature without the need for stoichiometric external reductants. By utilizing NaN3 as the electrolyte and graphite felt as both the cathode and the anode, we were able to selectively reduce the carbonyl groups of the substrates to alcohols, pinacols, or methylene groups by judiciously choosing the solvent and an acidic additive. The reaction conditions were compatible with a diverse array of functional groups, and phthalimides could undergo one-pot reductive cyclization to afford products with indolizidine scaffolds. Mechanistic studies showed that the reactions involved electron, proton, and hydrogen atom transfers. Importantly, an N3/HN3 cycle operated as a hydrogen atom shuttle, which was critical for reduction of the carbonyl groups to methylene groups.
Synthesis of Medium-Ring-Sized Benzolactams by Using Strong Electrophiles and Quantitative Evaluation of Ring-Size Dependency of the Cyclization Reaction Rate
Kurouchi, Hiroaki,Ohwada, Tomohiko
, p. 876 - 901 (2019/12/30)
Benzolactams with medium-sized rings were synthesized via the electrophilic aromatic substitution reaction of carbamoyl cations (R1R2N+═C═O) in good to high yields without dilution. These reactions were utilized to quantitatively examine the extent of retardation of medium-sized ring formation, compared to five- or six-membered ring formation. The order of reaction rates of formation of cyclic benzolactams is six- > five- > seven- > eight- > nine-membered ring at 25 °C. The present reaction provides a route to eight- A nd nine-membered benzolactams.
Investigation of the mechanism of C(sp3)-H bond cleavage in Pd(0)-catalyzed intramolecular alkane arylation adjacent to amides and sulfonamides
Rousseaux, Sophie,Gorelsky, Serge I.,Chung, Benjamin K. W.,Fagnou, Keith
supporting information; experimental part, p. 10692 - 10705 (2010/11/05)
The reactivity of C(sp3)-H bonds adjacent to a nitrogen atom can be tuned to allow intramolecular alkane arylation under Pd(0) catalysis. Diminishing the Lewis basicity of the nitrogen lone pair is crucial for this catalytic activity. A range of N-methylamides and sulfonamides react exclusively at primary C(sp3)-H bonds to afford the products of alkane arylation in good yields. The isolation of a Pd(II) reaction intermediate has enabled an evaluation of the reaction mechanism with a focus on the role of the bases in the C(sp3)-H bond cleaving step. The results of these stoichiometric studies, together with kinetic isotope effect experiments, provide rare experimental support for a concerted metalation-deprotonation (CMD) transition state, which has previously been proposed in alkane C(sp3)-H arylation. Moreover, DFT calculations have uncovered the additional role of the pivalate additive as a promoter of phosphine dissociation from the Pd(II) intermediate, enabling the CMD transition state. Finally, kinetic studies were performed, revealing the reaction rate expression and its relationship with the concentration of pivalate.
