Sulpholane––A new solvent for the Baylis–Hillman reaction

Dendritic compound of triphenylene-2,6,10-trione ketal-tri-{2,2-di-[(N-methyl-N-(4-pyridinyl) amino) methyl]-1,3-propanediol}: an easily recyclable catalyst for Morita-Baylis-Hillman reactions

“…In all cases only the normal Morita-Baylis-Hillman product was found [20,21,22]. The results were summarized in Table 1.…”

Novel aprotic polar solvents for facile Baylis-Hillman reaction

“…7 However, recent conditions employing DABCO in aqueous conditions 6 or protic solvent (MeOH) under the influence of microwave 13 or novel base 14 resulted in moderate to high yields of adducts, but only with select aldehydes. Since N-methylmorpholine is commercially used as a solvent apart from other uses, 11 reaction of acrylamide with aldehydes (2, 5, 7, 9-13) in N-methylmorpholine as solvent catalyzed by standard base (DABCO) at room temperature is conceived as an attractive proposition.…”

“…Particularly to bring the less reactive aldehydes like aliphatic aldehydes into the purview of this reaction, dioxane:water 6 solvent system played a crucial role. Similarly, towards this endeavor, sulpholane 7 was another important addition from our laboratories. Aprotic polar solvents are expected i) to eliminate the problem of ester hydrolysis (for ethyl/methyl acrylates) thus reducing their excess use, ii) to elevate the pKa of the base used (DABCO in the present study), iii) stabilization of the 'zwitterionic intermediate by chargedipole interactions.…”

Diazabicyclo[2.2.2]octane stabilized on Fe3O4 as catalysts for synthesis of coumarin under solvent-free conditions

“…DABCO has been applied as an inexpensive, eco-friendly, high reactive and non-toxic base catalyst for various organic transformations, including ring opening of aziridines with amines or thiols [14], oxidative deprotection of (tetrahydropyranyl) ethers and silyl ethers [15], conversion of tetrahydropyranyl ethers into acetates [16], regioselective nucleophilic aromatic substitution reaction [17], synthesis of isoxazolines [18], synthesis of N-arylphthalimides [19], synthesis of industrially important polyurethane foams [20], and Baylis-Hillman reactions [21,22]. Nevertheless, in many of these cases, DABCO has not been recovered, and eliminated as a residue.…”