Biobased Nonisocyanate Polyurethanes as Recyclable and Intrinsic Self-Healing Coating with Triple Healing Sites.

Polymer coatings having high amounts of renewable carbon and self-healing properties are highly sought after in a sustainability perspective. We report here the development of bio-/CO-derived nonisocyanate polyurethane (NIPU) coatings which are recyclable and healable via three different types of healing mechanisms. These NIPUs contain furan rings in their main chain which after cross-linking with bismaleimides form organogels having a thermo-reversible sol-gel transition and solvent-borne coatings with improved properties.

Synthesis of Mesoporous Copper Aluminosilicate Hollow Spheres for Oxidation Reactions.

Hollow functional metal silicate materials have received the most interest due to their large inner space, permeable and functional shell, lighter density, and better use of material compared to their solid counterparts. While tremendous success has been made in the synthesis of individual metal silicates with uniform morphology, the synthesis of multiphase hollow silicates has not been explored yet, although their direct applications could be promising. In this study, mesoporous aluminosilicate spheres (MASS) are transformed to submicrometer copper aluminosilicate hollow spheres (CASHS) via a one-pot hydrothermal process.

Efficient [Cu(NHC)]-Catalyzed Multicomponent Synthesis of Pyrroles.

Efficient [Cu(NHC)]-catalyzed syntheses of pyrroles via two and three-component coupling methods are described. Various 1,2-, 1,2,3-, 1,2,3,5- and fully substituted pyrroles were readily accessible through a suitable choice of ketone, primary amine and diol in a three-component reaction. The N-unsubstituted pyrrole formation is also feasible through a two-component reaction involving a β-amino alcohol and a ketone.

Copper-catalyzed oxidative amidation of aldehydes with amine salts: synthesis of primary, secondary, and tertiary amides.

A practical method for the amidation of aldehydes with economic ammonium chloride or amine hydrochloride salts has been developed for the synthesis of a wide variety of amides by using inexpensive copper sulfate or copper(I) oxide as a catalyst and aqueous tert-butyl hydroperoxide as an oxidant. This amidation reaction is operationally straightforward and provides primary, secondary, and tertiary amides in good to excellent yields for most cases utilizing inexpensive and readily available reagents under mild conditions. In situ formation of amine salts from free amines extends the substrate scope of the reaction.

Self-supported chiral titanium cluster (SCTC) as a robust catalyst for the asymmetric cyanation of imines under batch and continuous flow at room temperature.

A robust heterogeneous self-supported chiral titanium cluster (SCTC) catalyst and its application in the enantioselective imine-cyanation/Strecker reaction is described under batch and continuous processes. One of the major hurdles in the asymmetric Strecker reaction is the lack of availability of efficient and reusable heterogeneous catalysts that work at room temperature. We exploited the readily hydrolyzable nature of titanium alkoxide to synthesize a self-supported chiral titanium cluster (SCTC) catalyst by the controlled hydrolysis of a preformed chiral titanium-alkoxide complex.

Atmospheric pressure aminocarbonylation of aryl iodides using palladium nanoparticles supported on MOF-5.

An efficient amide synthesis by atmospheric pressure aminocarbonylation using palladium nanoparticles supported on MOF-5 is reported. Interestingly, only 0.5 wt% palladium loading was required to achieve high yields.

Stabilized well-dispersed Pd(0) nanoparticles for aminocarbonylation of aryl halides.

Well-dispersed palladium (0) nanoparticles stabilized with phosphonium based ionic liquid were synthesized conveniently and fully characterized. A catalyst system comprising of the Pd(0) nanoparticles and a base was found to be recyclable and efficient for the aminocarbonylation reaction of aryl iodide in ionic liquid media. In the presence of potassium tert-butyloxide, for the relatively stable aryl chloride and bromide substrates, medium activities were achieved for the catalyst.

Copper-catalyzed diacetoxylation of olefins using PhI(OAc)2 as oxidant.

Copper(I) or -(II) salts with weakly coordinating anions catalyze the diacetoxylation of olefins efficiently in the presence of PhI(OAc)(2) as the oxidant under mild conditions. The reaction is effective for aryl, aryl alkyl, as well as aliphatic terminal and internal olefins forming the corresponding vicinal diacetoxy compounds in 70-85% yields and dr (syn/anti) of up to 5.2.

Highly enantioselective titanium-catalyzed cyanation of imines at room temperature.

A highly active and enantioselective titanium-catalyzed cyanation of imines at room temperature is described. The catalyst used is a partially hydrolyzed titanium alkoxide (PHTA) precatalyst together with a readily available N-salicyl-beta-aminoalcohol ligand. Up to 98% ee was obtained with quantitative yields in 15 min of reaction time using 5 mol % of the catalyst.

Palladium nanoclusters supported on propylurea-modified siliceous mesocellular foam for coupling and hydrogenation reactions.

This paper describes the synthesis, characterization and applications of palladium (Pd) nanoparticles supported on siliceous mesocellular foam (MCF). Pd nanoparticles of 2-3 nm and 4-6 nm were used in reactions involving molecular hydrogen (such as hydrogenation of double bonds and reductive amination), transfer hydrogenation of ketones and epoxides, and coupling reactions (such as Heck and Suzuki reactions). They successfully catalyzed all these reactions with excellent yield and selectivity.

Catalytic asymmetric Pictet-Spengler reaction.

A catalytic asymmetric Pictet-Spengler reaction has been developed, wherein treating substituted tryptamines with an aldehyde in the presence of a catalytic amount of a chiral phosphoric acid provides the corresponding tetrahydro-beta-carboline derivatives in high yields and enantiomeric excesses. The reaction works well with both aliphatic and aromatic aldehydes.

Amines made easily: a highly selective hydroaminomethylation of olefins.

A highly chemo- and regioselective hydroaminomethylation of simple as well as functionalized alpha-olefins using a cationic rhodium precatalyst together with Xantphos as ligand is reported. Studies of the influence of ligands and reaction conditions led to an unprecedented selective hydroaminomethylation procedure. The novel procedure constitutes an economically attractive and environmentally favorable synthesis of secondary and tertiary aliphatic amines.

Internal olefins to linear amines.

The selective synthesis of linear amines from internal olefins or olefin mixtures was achieved through a catalytic one-pot reaction consisting of an initial olefin isomerization followed by hydroformylation and reductive amination. Key to the success is the use of specially designed phosphine ligands in the presence of rhodium catalysts. This reaction constitutes an economically attractive and environmentally favorable synthesis of linear aliphatic amines.

Synthesis of primary amines: first homogeneously catalyzed reductive amination with ammonia.

[reaction: see text] The synthesis of primary amines via reductive amination of the corresponding carbonyl compounds with aqueous ammonia is achieved for the first time with soluble transition metal complexes. Up to an 86% yield and a 97% selectivity for benzylamines were obtained in the case of various benzaldehydes by using a Rh-catalyst together with water-soluble phosphine and ammonium acetate. In the case of aliphatic aldehydes, a bimetallic catalyst based on Rh/Ir gave improved results.

Novel palladium(II) complex containing a chelating anionic N-O ligand: efficient carbonylation catalyst.

[reaction: see text] A novel palladium(II) complex containing chelating anionic pyridine-2-carboxylato and labile tosylato ligands is a highly efficient catalyst for the carbonylation of organic alcohols and olefins to carboxylic acids/esters. Carbonylation of primary, secondary, and tertiary alcohols as well as linear and functionalized terminal olefins was studied. In all cases remarkable activity and selectivity were observed.