Uranyl(VI) Triflate as Catalyst for the Meerwein–Ponndorf–Verley Reaction

Abstract

Catalytic transformation of oxygenated compounds is challenging in f-element chemistry due to the high oxophilicity of the f-block metals. We report here the first Meerwein−Ponndorf−Verley (MPV) reduction of carbonyl substrates with uranium-based catalysts, in particular from a series of uranyl(VI) compounds where [UO 2 (OTf) 2 ] (1) displays the greatest efficiency (OTf = trifluoromethanesulfonate). [UO 2 (OTf) 2 ] reduces a series of aromatic and aliphatic aldehydes and ketones into their corresponding alcohols with moderate to excellent yields, using i PrOH as a solvent and a reductant. The reaction proceeds under mild conditions (80 °C) with an optimized catalytic charge of 2.3 mol % and KO i Pr as a cocatalyst. The reduction of aldehydes (1−10 h) is faster than that of ketones (>15 h). NMR investigations clearly evidence the formation of hemiacetal intermediates with aldehydes, while they are not formed with ketones.

Photochemical separation of plutonium from uranium

“…These studies utilized pristine stock solutions containing only Pu 4+ (aq) or UO 2 2+ (aq) (vs. the Pu/U mixtures described above) and were carried out within the context of UO 2 2+ photochemistry results published previously in HNO 3(aq) . [29][30][31][32][33][34][35] For example, UO 2 2+ (aq) photoreduction to U 4+ (aq) has been shown to proceed with a variety of reductants, including triethylamine, 36 formate, 35 and 2-propanol. 14 We focused this study on 2-propanol, (CH 3 ) 2 CHOH, as a representative sacrificial electron donor (eqn (1) in Scheme 2).…”

Base-free transfer hydrogenation of aldehydes and ketones catalyzed by imidazolin-2-iminato actinide complexes

“…The conversion was found to be very low without a base (TOF 1.3 h −1 ) but increased in the presence of a base (TOF 35 h −1 ). 16 Warner et al reported the activity of plutonium( iii ) isopropoxide [Pu(O i Pr) 3 ] to act as a potent catalyst for the above-mentioned reaction, while [Th(O i Pr) 4 ], [U(O i Pr) 3 ] and [U(O i Pr) 4 ] were unexpectedly inactive. 17 Hence, the development of efficient organoactinide catalysts for the transfer hydrogenation of carbonyl compounds with isopropanol under neutral conditions is highly desirable from both synthetic and intellectual points of view.…”

“…The conversion was found to be very low without a base (TOF 1.3 h −1 ) but increased in the presence of a base (TOF 35 h −1 ). 16 17 Hence, the development of efficient organoactinide catalysts for the transfer hydrogenation of carbonyl compounds with isopropanol under neutral conditions is highly desirable from both synthetic and intellectual points of view.…”

Organodiphosphonate Zr‐MOF: A highly efficient catalyst for Meerwein–Ponndorf–Verley reduction of furfural

“…Catalytic transfer hydrogenation offers an alternative to H 2 for the reduction of C=O compounds 2–5 . Especially, the Meerwein–Ponndorf–Verley (MPV) reduction reaction with alcohols as H‐donors has received more attention 6–10 . The MPV reduction reaction process involves a cyclic six‐membered transition state in which both the alcohol and the C=O are coordinated to the same active center.…”

“…[2][3][4][5] Especially, the Meerwein-Ponndorf-Verley (MPV) reduction reaction with alcohols as H-donors has received more attention. [6][7][8][9][10] The MPV reduction reaction process involves a cyclic six-membered transition state in which both the alcohol and the C=O are coordinated to the same active center. This reduction reaction is highly selective for C=O; whereas, other possible reducible bonds, for example, C=C, are retained.…”