Search

Allylic amination, directly from alcohols, has been demonstrated without any Lewis acid activators using an efficient and regiospecific molecular iron catalyst. Various amines and alcohols were employed and the reaction proceeded through the oxidation/reduction (redox) pathway. A direct one-step synthesis of common drugs, such as cinnarizine and nafetifine, was exhibited from cinnamyl alcohol that produced water as side product.

Allylic amination, directly from alcohols, has been demonstrated without any Lewis acid activators using an efficient and regiospecific molecular iron catalyst. Various amines and alcohols were employed and the reaction proceeded through the oxidation/reduction (redox) pathway. A direct one-step synthesis of common drugs, such as cinnarizine and nafetifine, was exhibited from cinnamyl alcohol that produced water as side product.

Oxidative Heck reactions of arylboronic acids and alkenes are carried out in the presence of polyaniline-supported palladium catalysts using air as a co-oxidant to afford the Heck products with excellent yields and selectivities under base- and ligand-free conditions. The catalyst was recovered by simple filtration and used for several cycles with consistent activity.

Layered-double-hydroxide-supported nanorhodium catalyst (LDHRh(0)) was employed in the Heck-type coupling of alkenes 1 with arylboronic acids 2 to afford the corresponding substituted alkenes 3 in good to high yields (Table 1). The catalyst was separated by simple filtration and reused for five cycles with consistent activity.

Pd/C is used as an efficient catalyst for the copper-free Sonogashira coupling of acid chlorides and terminal alkynes to afford ynones in high yields (Tables 1 and 3). Cyclization of (2-methoxyaryl)-substituted ynones induced by I2/ammonium cerium(IV) nitrate (CAN) at room temperature gave 3-iodochromenones (=3-iodo-4H-1-benzopyran-4-ones) in excellent yield (Table 4).

Polyaniline-supported Sc, In, Pd, Os and Re catalysts were prepared by using a simple protocol and the thus prepared catalysts were well characterized using FTIR, XPS, UV-Vis/DRS, TGA-DTA. All the catalysts were successfully employed in a wide range of organic transformations such as cyanation and allylation of carbonyl compound, Suzuki coupling of aryl halides and boronic acids, and, most importantly, in asymmetric dihydroxylation of olefins to afford optically active vicinal diols. All the catalysts were separated from the reaction mixture by simple filtration and reused with consistent activity for five cycles without noticeable leaching of metal from the support.

Layered double hydroxide (LDH)-supported nanoplatinum(0) and nanopalladium(0) catalysts were prepared by a simple ion exchange technique and subsequent reduction with hydrazine hydrate and used for the allylation of aldehydes to give moderate to good yields of homoallylic alcohols. Detailed mechanistic studies of LDH-Pd(0)-catalyzed allylation using XPS and TGA-MS reveal that a monoallyl-palladium complex is the key intermediate for the catalytic cycle.

A nanocrystalline magnesium oxide-stabi- lized palladium(0) catalyst is prepared by counterion stabilization of PdCl4 2 � with nanocrystalline MgO fol- lowed by reduction. This ligand-free heterogeneous nanocrystalline MgO-stabilized nanopalladium (NAPMgPd(0)) catalyst using the basic MgO in place of basic ligands exhibits excellent activity in Su- zuki and Stille cross-coupling of haloarenes (chloro, bromo and iodo) to afford the unsymmetrical biaryls. The catalyst is quantitatively recovered by simple fil- tration and reused for four cycles with almost consis- tent activity.

New bifunctional catalysts composed of PdCl 4 2- , OsO 4 2- and OsO 4 2- , WO 4 2- designed and prepared by a counterionic stabilization technique involving the reactions of Na 2 PdCl 4 -K 2 OsO 4 and K 2 OsO 4 -Na 2 WO 4 with nanocrystalline MgO are well characterized. These bifunctional catalysts, NAP-Mg-PdOs and NAP-Mg-OsW perform tandem Heck asymmetric dihydroxylation and asymmetric dihydroxylation-N-oxidation reactions, respectively, in the presence of the chiral ligand 1,4-bis(9-o-dihydroquinidinyl)phthalazine [(DHQD) 2 PHAL] in a single pot. It is quite impressive to note that H 2 O 2 is used as a terminal oxidant to provide N-methylmorpholine N-oxide (NMO) in situ by the oxidation of N-methylmorpholine (NMM) in the asymmetric dihydroxylation-N-oxidation catalyzed by NAP-Mg-OsW.

Flaxseed Lignan Secoisolariciresinol Diglucoside Improves Insulin Sensitivity through Upregulating GLUT4 Expression in Diet-Induced Obese Mice Yanwen Wang1, Bourlaye Fofana2, Moumita Roy1, and Kaus...

Layered-double-hydroxide-supported nanorhodium catalyst (LDHRh(0)) was employed in the Heck-type coupling of alkenes 1 with arylboronic acids 2 to afford the corresponding substituted alkenes 3 in good to high yields (Table 1). The catalyst was separated by simple filtration and reused for five cycles with consistent activity.

Oxidative Heck reactions of arylboronic acids and alkenes are carried out in the presence of polyaniline-supported palladium catalysts using air as a co-oxidant to afford the Heck products with excellent yields and selectivities under base- and ligand-free conditions. The catalyst was recovered by simple filtration and used for several cycles with consistent activity.

Silica-supported tetramethylguanidine catalyst was prepared and effectively used in the aldol-type coupling of aldehydes with ethyl diazoacetate to afford the corresponding α-diazo-β-hydroxy esters in good to excellent yields. The catalyst was quantitatively recovered from the reaction by a simple filtration and reused for a number of cycles with almost consistent activity.

A 3-aminopropyl-functionalized silica-supported rhodium(0) catalyst (SiO2–Rh0) was prepared and employed in the Heck-type coupling of arylboronic acids and alkenes, affording good-to-excellent yields of substituted alkenes; the catalyst was recovered by filtration and reused for several cycles.

Polyaniline supported palladium catalysts were prepared from different palladium precursors and all the catalysts are well characterized using ICP-AES, FTIR, TGA–DTA, SEM-EDX and XPS analysis. All the catalysts were tested for Suzuki–Miyaura coupling of bromo- and chloroarenes in water and the catalyst prepared from PdCl2 precursor was found to be the most effective catalyst. The catalyst can easily be recovered by simple filtration and reused for several cycles with almost consistent activity.