Hydrogen-bonding organocatalysts for ring-opening polymerization

Thomas, Coralie; Bibal, Brigitte

doi:10.1039/c3gc41806e

Cited by 240 publications

(201 citation statements)

References 116 publications

Supporting

Mentioning

196

Contrasting

Order By: Relevance

“…[10] Furthermore, they find extensive applications as precursors of ancillary ligands forn umerous transition-,l anthanoid-, and main-group-metal complexes [11] and they can also be employed as organocatalysts. [12] Atom-economical catalytic addition of aminestocarbodiimides (guanylation reaction, Scheme 1) constitutes one of the most straightforwardr outes to accessN -substituted guanidines. [9] Althoughc ertain guanylationsc an be accomplished catalystfree, thesep rocesses have high kinetic barriers that require the use of harsh reaction conditions, which restricts their application to activated primary aliphatic amines.…”

Section: Introductionmentioning

confidence: 99%

Structural and Mechanistic Insights into s‐Block Bimetallic Catalysis: Sodium Magnesiate‐Catalyzed Guanylation of Amines

Tullio

Hernán‐Gómez

Livingstone

et al. 2016

Chemistry A European J

View full text Add to dashboard Cite

To advance the catalytic applications of s-block mixed-metal complexes, sodium magnesiate [NaMg(CH SiMe ) ] (1) is reported as an efficient precatalyst for the guanylation of a variety of anilines and secondary amines with carbodiimides. First examples of hydrophosphination of carbodiimides by using a Mg catalyst are also described. The catalytic ability of the mixed-metal system is much greater than that of its homometallic components [NaCH SiMe ] and [Mg(CH SiMe ) ]. Stoichiometric studies suggest that magnesiate amido and guanidinate complexes are intermediates in these catalytic routes. Reactivity and kinetic studies imply that these guanylation reactions occur via (tris)amide intermediates that react with carbodiiimides in insertion steps. The rate law for the guanylation of N,N'-diisopropylcarbodiimide with 4-tert-butylaniline catalyzed by 1 is first order with respect to [amine], [carbodiimide], and [catalyst], and the reaction shows a large kinetic isotopic effect, which is consistent with an amine-assisted rate-determining carbodiimide insertion transition state. Studies to assess the effect of sodium in these transformations denote a secondary role with little involvement in the catalytic cycle.

show abstract

Section: Introductionmentioning

confidence: 99%

Structural and Mechanistic Insights into s‐Block Bimetallic Catalysis: Sodium Magnesiate‐Catalyzed Guanylation of Amines

Tullio

Hernán‐Gómez

Livingstone

et al. 2016

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…2–5 This class of compounds features a wide array of functional motifs and geometries and has been employed in a multitude of reactions including Henry reactions, hydroaminations, conjugate additions and ring-opening polymerization (ROP). 6–12 While the wealth of chemistry offered by H-bonding catalysts has attracted numerous research groups, these systems can require high catalyst loadings and/or long reaction times.…”

Section: Introductionmentioning

confidence: 99%

Rate Accelerated Organocatalytic Ring-Opening Polymerization of l-Lactide via the Application of a Bis(thiourea) H-bond Donating Cocatalyst

et al. 2015

View full text Add to dashboard Cite

A cocatalyst system consisting of an alkylamine base and a bis(thiourea) featuring a linear alkane tether is shown to dramatically increase the rate of ring-opening polymerization (ROP) of L-lactide versus previously disclosed monothiourea H-bond donors. Rate acceleration occurs regardless of the identity of the alkylamine cocatalyst, and the ROP remains controlled yielding poly(lactide) with narrow molecular weight distributions, predictable molecular weights and high selectivity for monomer. This H-bond mediated ROP of L-lactide constitutes a rare, clear example of rate acceleration with bis(thiourea) H-bond donors versus monothioureas, and the bis(thiourea) is shown to remain highly active for ROP at fractional percent catalyst loadings. Activation at a single monomer ester by both thiourea moieties is implicated as the source of rate acceleration.

show abstract

“…Organocatalysis for polymerization reactions is a field that has gained a huge interest these last 15–20 years, notably in a sustainable chemistry background . Most of the studies were devoted to chain growth reactions, especially the ring‐opening polymerization of various types of heterocycles and the polymerization of acrylic and methacrylic monomers.…”

Section: Introductionmentioning

confidence: 99%

Organocatalysts for the Synthesis of Poly(ethylene terephthalate‐co‐isosorbide terephthalate): A Combined Experimental and DFT Study

Stanley

Chenal

Jacquel

et al. 2019

Macro Materials & Eng

View full text Add to dashboard Cite

Organocatalysts are assessed for the insertion of isosorbide, a rigid, biobased diol monomer, into poly(ethylene terephthalate). A sulfonic acid (p‐toluenesulfonic acid—APTS), an amidine base (1,8‐diazabicyclo [5.4.0] undec‐7‐ene—DBU) and a guanidine base (1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene—TBD) successfully catalyze the polymerization. The reaction mechanisms are studied by density functional theory. A bifunctional activation is observed in the presence of the sulfonic acid, the carbonyl moiety being activated via the acidic proton of APTS and the alcohol via the basic oxygen. Regarding DBU, a mechanism based on a basic activation of the alcohol rather than a nucleophilic attack of the catalyst is evidenced. The difference observed between TBD and DBU is attributed to a better H‐bonding ability of the former versus the latter.

show abstract

Hydrogen-bonding organocatalysts for ring-opening polymerization

Cited by 240 publications

References 116 publications

Structural and Mechanistic Insights into s‐Block Bimetallic Catalysis: Sodium Magnesiate‐Catalyzed Guanylation of Amines

Structural and Mechanistic Insights into s‐Block Bimetallic Catalysis: Sodium Magnesiate‐Catalyzed Guanylation of Amines

Rate Accelerated Organocatalytic Ring-Opening Polymerization of l-Lactide via the Application of a Bis(thiourea) H-bond Donating Cocatalyst

Organocatalysts for the Synthesis of Poly(ethylene terephthalate‐co‐isosorbide terephthalate): A Combined Experimental and DFT Study

Contact Info

Product

Resources

About