The use of a heterogeneous Lewis acid catalyst, which is insoluble and easily separable during the reaction, is a promising option for hydrolysis reactions from both environmental and practical viewpoints. In this study, ceria showed excellent catalytic activity in the hydrolysis of 4-methyl-1,3-dioxane to 1,3-butanediol in 95% yield and in the one-pot synthesis of 1,3-butanediol from propylene and formaldehyde via Prins condensation and hydrolysis reactions in an overall yield of 60%. In-depth investigations revealed that ceria is a water-tolerant Lewis acid catalyst, which has seldom been reported previously. The ceria catalysts showed rather unusual high activity in hydrolysis, with a turnover number (TON) of 260, which is rather high for bulk oxide catalysts, whose TONs are usually less than 100. Our conclusion that ceria functions as a Lewis acid catalyst in hydrolysis reactions is firmly supported by thorough characterizations with IR and Raman spectroscopy, acidity measurements with IR and 31P magi...

Heterogeneous ceria catalyst with water-tolerant Lewis acidic sites for one-pot synthesis of 1,3-diols via Prins condensation and hydrolysis reactions.

A highly active and site selective indium catalyst for lactide polymerization

Fused-ring and bridged-ring tetrahydrofuran scaffolds are found in a number of natural products and biologically active compounds. A new copper-catalyzed intramolecular carboetherification of alkenes for the synthesis of bicyclic tetrahydrofurans is reported herein. The reaction involves Cu-catalyzed intramolecular addition of alcohols to unactivated alkenes and subsequent aryl C–H functionalization provides the C–C bond. Mechanistic studies indicate a primary carbon radical intermediate is involved and radical addition to the aryl ring is the likely C–C bond-forming mechanism. Preliminary catalytic enantioselective reactions are promising (up to 75% ee) and provide evidence that copper is involved in the alkene addition step, likely through a cis-oxycupration mechanism. Catalytic enantioselective alkene carboetherification reactions are rare and future development of this new method into a highly enantioselective process is promising. During the course of the mechanistic studies a protocol for alkene hyd...

/pdf/copper-catalyzed-intramolecular-alkene-carboetherification-4fcj2zjwhd.pdf

Copper-Catalyzed Intramolecular Alkene Carboetherification: Synthesis of Fused-Ring and Bridged-Ring Tetrahydrofurans

The metal-catalysed hydrofunctionalisation of alkenes and alkynes provides a convenient and atom-economic route to diversely functionalised products with control of regio-, chemo- and stereoselectivity. As one of the most abundant elements on earth, iron offers a level of sustainable and long-term availability that is uncommon for most transition metals. Although iron is commonly found in the oxidation states of +2 and +3, the use of redox-active ligands has allowed the synthesis and application of low oxidation state iron complexes in catalysis. A broad range of hydrofunctionalisation reactions have been developed by using iron catalysts in a wide variety of oxidation states. Intense development over the past decade has resulted in the development of iron-catalysed hydroamination, hydroalkoxylation, hydrocarboxylation, hydrothiolation, hydrovinylation, hydrosilylation, hydroboration, hydrophosphination, hydromagnesiation and carbonylation reactions, amongst others. With the field still in its infancy, there is great potential for further developments in the mechanistic understanding and synthetic and industrial applicability of these processes.

Iron-Catalysed Hydrofunctionalisation of Alkenes and Alkynes

Recent Developments in Metal-Catalyzed Additions of Oxygen Nucleophiles to Alkenes and Alkynes

The hydroalkoxylation of dicyclopentadiene (DCPD) and norbornene (NB) with 2-hydroxyethyl methacrylate (HEMA) for the synthesis of industrially relevant monomers has been investigated with various metal-based Lewis acids and strong Bronsted acids. In the absence of other additives, copper(II) triflate is the most efficient catalyst system. Kinetics, electron spin resonance (ESR), catalyst poisoning and cross experiments indicate that triflic acid (TfOH) is the true active catalyst in these reactions. This in situ generation of TfOH occurs via reduction of Cu(OTf) 2 by the olefin reagent (DCPD, NB). The copper ions present in the reaction mixture act as radical polymerization retardants, preventing polymerization of HEMA (which is observed with most other metal salts and strong Bronsted acids investigated), thus improving the selectivity and yield (up to 95%) for the desired products. These observations have led to the development of a highly effective green process, using bulk reagents (no solvent) and a cheap, metal-free catalyst system, based on TfOH and a phenolic radical inhibitor (2,5-di-tert-butylhydroxytoluene, BHT).

Copper(II) Triflate as a Source of Triflic Acid: Effective, Green Catalysis of Hydroalkoxylation Reactions

https://www.rsc.org/suppdata/py/c1/c1py00145k/c1py00145k.pdf

Indium(III) halides as exceptionally active, water-tolerant catalysts for cationic polymerization of styrenics

The invention concerns a sulphur product obtained by additive reaction of at least a polythiol (I), (A) on at least a compound of formula (II): wherein R1 represents an aliphatic radical, linear or branched, comprising a double ethylenically unsaturated bond, the latter capable of being the one whereby R1 is bound to the norbornene cycle, said cycle capable of further comprising other substituents selected among C?1?-C3 alkyl, in proportions corresponding or substantially corresponding to a thiol group of the polythiol(s) (I) per mole of the compound(s) (II), the thiol groups of the compound(s) (I) having been added for the most part on the cyclic double bond of the compound(s) (II) and, on average, one ethylene unsaturation of a compound (II) of the two it carries having been left free; or (B) on at least a cross-linkable product (P), such as one obtained as per point (A) above, the double bonds of said product (P) having been completely or substantially completely consumed, the resulting product (P') being a cross-linked product.

Sulphur products for adding a polythiol on a norbornene derivative, preparation method and use for obtaining radical cross-linking products

Water-tolerant catalyst systems for the bulk cationic polymerization of para-methylstyrene and indene

These compositions comprise at least one compound (A) containing double olefinic bonds depleted of electrons and at least one compound (B) containing double olefinic bonds enriched with electrons. The compound(s) (A) are selected among prepolymers comprising maleimid functions (f) consisting in the reaction products of at least one maleic anhydride (I), of at least one compound (II) having at least one -NH2 function and at least one other function F: -OH, -NH2, -NH-, -COOH, or -COOR3 or -OCOR?3 (R3 = C?1-C5 alkyl) and at least one chain forming compound (III) by polycondensation and/or polyaddition; (II) having been first reacted with (I) to open the maleic anhydride cycles, with formation of maleamic acid functions (f) which have then been at least partially re-closed by heat to produce N-substituted maleimids by groups functionalised by F; the chain having been formed by polycondensation and/or polyaddition of the N-substituted maleimid bearing the function F of compound(s) (III), of non aromatised products bearing a function F or not formed at the same time as said N-substituted maleimids, and of the maleic anhydride(s) (I) which could have been in excess after being. opened by the compound(s) (II); the functionalities and proportions of (II) and (III) having been selected so as to preclude a gelation of the reaction medium. In (a) (f), (I), and (f'), R1, R2 = H, C?1?-C12 alkyl or halogen.

Coating compositions polymerisable and/or cross-linkable by ultraviolet or visible light

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