Sequential Suzuki/Asymmetric Aldol and Suzuki/Knoevenagel Reactions Under Aqueous Conditions

Abstract

Here we describe for the first time a sequential Suzuki/asymmetric aldol reaction. Such sequential approach was achieved through the combined use of an ionic liquid supported palladium catalyst and the organocatalyst trans-4-(2,2-diphenylacetoxy)proline. Suzuki and asymmetric aldol reactions were performed under aqueous conditions. The use of a palladium catalyst under basic conditions allowed also the first example of sequential Suzuki/Knoevenagel reaction.\ud Reactions were carried out under aqueous conditions and products were isolated in good to high yields and, in the case of the Suzuki/aldol reaction, with diastereoselectivities up to 91:9 and enantioselectivities up to at least 99%

One-pot sequential oxidation and aldol-condensation reactions of veratryl alcohol catalyzed by the Ru@ZIF-8 + CuO/basic ionic liquid system

“…Ionic liquids (ILs) with negligible vapor pressure, high thermal stability, and high gas solubility can be used as reaction media for replacing volatile and hazardous organic solvents. 15 Among them, basic ionic liquid (BIL) has been utilized in some base-catalyzed processes such as Heck, 16 Suzuki, 17 aldol condensation, 18 Henry 19 and Knoevenagel reactions. 20 The main advantage of using BILs is that they can function as both base and solvent.…”

2.14 Other Condensation Reactions (Knoevenagel, Perkin, Darzens)

“…61 Basic conditions of the Suzuki-Miyaura coupling using SiO 2 -supported Pd catalyst 62 could operate in the Knoevenagel condensation under aqueous conditions without the use of amine catalyst. 63 This situation allowed for a combination of the Suzuki-Miyaura coupling of aryl halides 61 and phenylboronic acid (62) A multicomponent reaction between aromatic aldehydes (64), 2-nitromethylenethiazolidine (65), and nitriles 66 in the presence of Et 3 N afforded a series of 5-amino-7-aryl-8-nitrothiazolo[3,2-a]pyridines (67) (Scheme 21, Table 4). 64 This one-pot multicomponent reaction was initiated by the Knoevenagel reaction of aldehyde with nitrile compound, followed by conjugated addition of enamine and cyclization.…”

Synthesis and styrene copolymerization of novel ring-substituted isobutyl phenylcyanoacrylates

“…4-Phenoxy ring-substituted phenylcyanoacrylate was involved in DBU-mediated [4 + 2] annulations of cyclopropanes with 3-aryl-2cyanoacrylates for the synthesis of fully substituted anilines [7], and in studies on quinolin-2(1H)-one derivatives related to synthetic access to pyrano [3,2-c] quinoline and 3substituted quinoline derivatives [8]. 4'-Methyl[1,1'-biphenyl]-4-yl-substituted phenylcyanoacrylate was reported in synthesis of biaryl derivatives by sequential strategies via Suzuki coupling/Knoevenagel condensation [9,10]. 4-Acetoxy ring-substituted phenylcyanoacrylate was involved in synthesis of tetrahydrobenzo [b]pyran in water catalyzed by heterogeneous amine grafted on silica [11]; in Knoevenagel reactions with nano-silica PAMAM dendrimer as catalyst [12], and with amine supported on silica gel [13].…”