Synthesis and Recovery of Pyridine- and Piperidine-based Camphorsulfonamide Organocatalysts Used for Michael Addition Reaction

Abstract

Two new pyridine-based asymmetric bifunctional organocatalysts containing one or two camphorsulfonamide units were synthesized. Asymmetric Michael addition of pentane-2,4-dione to β-nitrostyrene was catalyzed by these organocatalysts. During our experiments, influence of the solvent and temperature on the yield and enantioselectivity was studied. Using monocamphorsulfonamide derivative the S enantiomer of the corresponding Michael adduct was gained with moderate yield (up to 51 %) and low enantiomeric excess (up to 18 %). Organic solvent nanofiltration was successfully applied for the recovery of these organocatalysts. Furthermore, pyridine camphorsulfonamide was reduced to its piperidine derivative. Using piperidine monosulfonamide derivative racemic Michael adduct was obtained with excellent yield (up to 89 %). Beside its organocatalytic relevance, piperidine monosulfonamide derivative may also possess biological activity.

Membrane-Supported Recovery of Homogeneous Organocatalysts: A Review

“…Therefore, for suitable industrial procedures, practically 99.99% retention of the catalyst is needed [2]. This essential requirement is supported by our observations on the membrane-assisted recovery of crown ethers and camphorsulfonamides [45,46]. In Figure 2, a schematic representation of an ideal OSN-assisted catalyst recycling is presented, where the molecular weight (MW) of the catalyst is manyfold higher than that of the product.…”

Organic Solvent Nanofiltration in Pharmaceutical Applications

“…Besides the Pd, Rh and Ru catalysts, some other homogeneous catalysts such as gold-based, − platinum-based, tungsten-based, − magnesium triflate, , Co-Jacobsen catalyst, and quinidine-based organocatalyst − have been explored for recovery/recycling. For example, gold N-heterocyclic carbene complexes in the hydration of diphenylacetylene (Scheme ) were first recovered by Bayrakdar et al The Borsig oNF-1 membrane was selected due to its high rejection toward the catalyst (98.5%) and moderate rejection toward the product (53%) in the mixture of THF/water.…”

Applying Heterogeneous Catalytic Reactions for Organic Chemical Syntheses

“…Based on their pK a measurements, these crown ethers containing N-heterocyclic moiety can be applied as bifunctional organocatalysts, for instance, in Michael addition reactions [29]. Later, a piperidine-based camphorsulfonamide derivative was also prepared from the corresponding pyridine derivative in 78% yield by using our aforementioned catalytic hydrogenation method [30]. It was also used for some Michael addition reactions as an organocatalyst.…”