Chemoselective Heterogeneous Hydrogenation of Sulfur Containing Quinolines under Mild Conditions

Abstract

Sulfur, alongside oxygen and nitrogen, holds a prominent position as one of the key heteroatoms in nature and medicinal chemistry. Its significance stems from its ability to adopt different oxidation states, rendering it valuable as both a polarity handle and a hydrogen bond donor/acceptor. Nevertheless, the poisonous nature of its free electron pairs makes sulfur containing substrates inaccessible for many catalytic protocols. Strong and (at low temperatures) irreversible chemisorption to the catalyst's surface is in particular detrimental for heterogeneous catalysts, possessing only few catalytically active sites. Herein, we present a novel heterogeneous Ru−S catalyst that tolerates multiple sulfur functionalities, including thioethers, thiophenes, sulfoxides, sulfones, sulfonamides, and sulfoximines, in the hydrogenation of quinolines. The utility of the products was further demonstrated by subsequent diversifications of the sulfur functionalities.

Optimization of heterogeneous continuous flow hydrogenation using FTIR inline analysis: a comparative study of multi-objective Bayesian optimization and kinetic modeling

“…Heterogeneous catalytic hydrogenation is pivotal in organic synthetic chemistry, with broad applications across the dye, pharmaceutical, and fine chemical industries. [1][2][3] Traditional intermittent hydrogenation processes, however, are constrained by critical safety concerns associated with reaction temperature and pressure, prompting a shift towards continuous flow hydrogenation as a safer and more efficient alternative. [4,5] The reaction optimization within these continuous flow systems has emerged as a research focus.…”

Co(II)-Catalyzed Additive-Free Transfer Hydrogenation of N-Heteroarenes at Room Temperature

“…Given their prime importance as a potential LOHC, these motifs are quite indispensable for a hydrogen-based economy . Direct hydrogenation of N -heteroarene counterparts is the most straightforward method to access these molecules . Due to operational simplicity, safety, and high functional group tolerance, catalytic transfer hydrogenation (CTH) utilizing sacrificial hydrogen donors has gained significant attention .…”