Polystyrene-Supported Phosphine-Catalyzed aza-Baylis−Hillman Reactions and the Relationship between Resin Loading Level and Catalyst Efficiency

Chiral catalysts immobilized on achiral polymers: effect of the polymer support on the performance of the catalyst

“…Toy and coworkers have also demonstrated a direct relationship between catalytic efficiency, crosslinker nature, catalyst loading and swelling in the aza-Baylis-Hillman reactions catalysed by JandaJel-PPh 3 . 99,100 Similar effects were observed in the work of Pedrosa, Andres and coworkers with a series of chiral ureas and thioureas immobilized on PS-DVB resins by either grafting and copolymerisation methodologies and studied for the aza-Henry reaction between N-Boc-benzaldimine (18) and nitromethane (19) under solvent free conditions (Fig. 4).…”

One-pot sequential synthesis of isocyanates and urea derivatives via a microwave-assisted Staudinger–aza-Wittig reaction

“…With the aim to overcome cost limitations we recently described the preparation of triphenylphosphine-loaded cross-liked cyclodextrin complexes as recyclable green catalyst [39]. The reactivity of polystyrene-supported reagents strongly depends on the choice of solvent that can influence polymer swelling [40]. Solvent choice is therefore an important issue as it must allow the supported reagent to work in a friendly environment and, at the same time, facilitate the reaction outcome.…”

Optimization of Polystyrene‐Supported Triphenylphosphine Catalysts for Aza‐Morita—Baylis—Hillman Reactions.

“…Since we previously examined 1a in AMBH reactions of a range of N-tosyl arylimines with only electrophile 6, 20 we wanted to see if other Michael acceptors, such as acrolein (8) and phenyl acrylate (10), are also useful in this reaction system. The results of AMBH reactions catalyzed by 1f of 8 and 10 with a variety of electrophiles 5 are summarized in Tables 4 and 5, respectively.…”

“…We have recently reported both soluble and insoluble amine, 10 arsine, 11 ketone, 12 nitroxyl, 13 phosphine, 14 sulfide, 15 sulfonamide, 16 and sulfoxide 17 reagents that are useful in a wide range of synthetic transformations. In a bridging of our areas of interest, we have examined the use of a soluble poly(ethylene glycol)-supported phosphine, 18 and insoluble polystyrene-supported DMAP 18,19 and PPh 3 (JandaJel-PPh 3 , 1a, Scheme 2) 20,21 reagents as nucleophilic catalysts in AMBH reactions 22 and observed results similar to those obtained using the analogous small molecule catalysts. 23 In this later report, we examined the relationship between resin loading level and catalyst efficiency and observed that a loading level of 1.5 mmol PPh 3 /g of resin was optimal.…”