Highly efficient one-pot, three-component Mannich reaction catalysed by boric acid and glycerol in water with major ‘syn’ diastereoselectivity

Brown carbon formation from ketoaldehydes of biogenic monoterpenes

“…Because the proposed C 18 H 23 NO 3 Schiff base is an organic compound containing both an imine group and a carboxylic acid group, strong intramolecular H-bonding (via a 7-member ring) may lead to zwitterion formation by protonation of the imine by the acid. 69 We note there are other reaction pathways leading to a C 18 H 23 NO 3 molecule stemming from the observed compounds in aqueous media, such as organic acidcatalysed Mannich-type reaction between enols and imines 70,71 or transimination of an imine and amine. [72][73][74] However, the proposed reaction mechanism satises the following criteria: it requires only mild organic acid catalysis and it occurs in aqueous solution.…”

Silica-Supported Boric Acid with Ionic Liquid: A Novel Recyclable Catalytic System for One-Pot Three-Component Mannich Reaction

“…80°C indicated kinetically controlled anti product formation. 29) As far as the mechanism of the reaction is concerned, it has been presumed that oxygen of borosiloxane (Si-O-B) bond in H 3 BO 3 -SiO 2 interacts with imdazolium cation of ionic liquid resulting in polarization of Si-O and Si-O-B bonds with subsequent stabilization by anion of ionic liquid. Polarized Si-O bonds interact with O-H bond of enol to form desired product (Fig.…”

“…14) Numbers of catalysts have been employed for classical Mannich reaction of aldehydes, ketones and amines mainly involving acids like proline, [15][16][17] p-dodecyl benzenesulphonic acid (DBSA) 18) and some Lewis acids. [19][20][21] Other catalysts for the reaction include Yb(OiPr) 3 , 22) InCl 3 , 23,24) lanthanide triflate 25) in solvents like dichloromethane and acetonitrile, siloxy serine organocatalysts, 26) phosphorodiamidic acid, 27) bromodimethylsulfonium bromide 28) and boric acid/glycerol, 29) 4-hydroxypyrrolidine, 30) Trypsin, 31) Yb/K heterobimetallic catalyst. 32) Some solid-supported catalysts have also been used such as AlCl 3 -SiO 2 , 33) HClO 4 -SiO 2 34) and H 2 SO 4 -SiO 2 .…”

Kinetic and Mechanistic Investigation of Pyrano[2,3-d]pyrimidine Formation in the Presence of Catalyst under Novel One-Pot Three-Component Reaction

“…Multicomponent reactions (MCRs) involving pot, atom, and step-economy have received substantial consideration from the organic community due to their advantages over conventional multistep synthesis [1][2][3][4][5][6]. This kind of reactions have some advantages over conventional linear syntheses, including shorter reaction times, lower costs, high atom-economy, energy saving, the possibility for combinatorial surveying of structural variations, and environmental friendliness.…”