Polymerizability of <i>Exo</i>‐methylene‐lactide toward vinyl addition and ring opening

Miyake, Garret M.; Zhang, Yuetao; Chen, Eugene Y.‐X.

doi:10.1002/pola.27629

Cited by 22 publications

(20 citation statements)

References 59 publications

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“…ROP of 1 is also unproductive (Supporting Information Table S2 ), instead promoting monomer decomposition. In line with work by Miyake et al, we confirmed that 1 prefers regio‐selective alcoholysis rather than productive ring‐opening, with the benzyl alcohol initiator initially serving as the alcohol source. Addition of alternative alcohols generated a family of new small molecule products (Supporting Information Scheme S1 ).…”

Section: Resultssupporting

confidence: 91%

Cross‐metathesis functionalized exo‐olefin derivatives of lactide

Sinclair

Shaver

2018

J. Polym. Sci. Part A: Polym. Chem.

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Poly(lactic acid) is at the forefront of research into alternative replacements to fossil fuel derived polymers, yet preparation of derivatives of this key biodegradable polymer remain challenging. This article explores the use of two derivatives of lactide, each of which features an exocyclic olefin, and their pre‐polymerization modification by olefin cross‐metathesis. Methylenation of lactide with Tebbe's reagent generates a novel 5‐methylenated lactide monomer, (3S,6S)‐3,6‐dimethyl‐5‐methylene‐1,4‐dioxan‐2‐one, complementing the previously reported 3‐methylenated (6S)‐3‐methylene‐6‐methyl‐1,4‐dioxan‐2,5‐dione. While ring‐opening of each monomer is not productive, olefin cross‐metathesis can be used to functionalize each of the exocyclic olefins to produce a family of monomers. The ring‐opening polymerization of these new monomers, and their hydrogenated congeners, is facilitated by organo‐ and Lewis‐acid catalysts. Together, they offer a new strategy for derivatizing and altering the properties of poly(lactic acid). © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 741–748

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Section: Resultssupporting

confidence: 91%

Cross‐metathesis functionalized exo‐olefin derivatives of lactide

Sinclair

Shaver

2018

J. Polym. Sci. Part A: Polym. Chem.

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“…Several recent reports have indicated that Zr, Zn, or Li enolates can initiate lactide polymerization. 18–22 …”

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confidence: 99%

Cyclopropenimine Superbases: Competitive Initiation Processes in Lactide Polymerization

et al. 2015

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Cyclopropenimine superbases were employed to catalyze the ring-opening polymerization of lactide. Polymerization occurred readily in the presence and absence of alcohol initiators. Polymerizations in the absence of alcohol initiators revealed a competitive initiation mechanism involving deprotonation of lactide by the cyclopropenimine to generate an enolate. NMR and MALDI-TOF analysis of the poly(lactides) generated from cyclopropenimines in the absence of alcohol initiators showed acylated lactide and hydroxyl endgroups. Model studies and comparative experiments with guanidine and phosphazene catalysts revealed the subtle influence of the nature of the superbase on competitive initiation processes.Organocatalysis has proven a versatile strategy for ring-opening polymerization reactions. [1][2][3][4][5] Organic molecules catalyze ring-opening polymerization (ROP) by a variety of mechanisms that are distinct from those of metal alkoxide initiators; the mild conditions and high functional group tolerance of many of these organic catalysts have provided new opportunities for macromolecular synthesis and design. 1,2 Superbases 6 such as Nheterocyclic carbenes (NHCs), guanidines, amidines, isothioureas, and phosphazenes have proven especially effective as organic catalysts for ROP; in the presence of alcohol initiators these catalysts can hydrogen bond to the alcohol or chain-ends to activate them for the ringopening of strained monomers (Scheme 1, illustrated for lactide). 2 At low initiator (alcohol) concentrations, competitive initiation mechanisms can occur and can be probed by carrying out polymerizations in the absence of alcohols. 2,7 In the absence of alcohol initiators, Nheterocyclic carbenes, 8,9 amidines, 10 and isothioureas 11 mediate zwitterionic ring-opening polymerization reactions by a nucleophilic 12 mechanism; this latter strategy has proven useful for generating cyclic macromolecules. 9 Herein, we describe ring-opening polymerization reactions with another class of potent neutral bases derived from bis(dialkylamino)-cyclopropenimines. [13][14][15] Lambert recently showed that these compounds have comparable basicity to phosphazenes, are readily *Corresponding Author: waymouth@stanford.edu. ASSOCIATED CONTENT NMR Spectra, GPC traces, MALDI and ESI-MS of polymers and model studies. This material is available free of charge via the Internet at http://pubs.acs.org HHS Public AccessThree achiral cyclopropenimines bearing N-alkyl substituents (Table 1, right inset) were prepared. [13][14][15] Polymerizations of lactide initiated with 1-pyrenebutanol in the presence of catalytic amounts of cyclopropenimine 1 proceeded rapidly with greater than 85% conversion in 30 seconds (Table S1, Supporting Information). Molecular weights up to 13 kDa were obtained by controlling the monomer to alcohol ratio. The molecular weight distributions ranged from 1.2-1.4 and generally increased over the course of the reaction. These data, coupled with the observations that polymeric ions corresponding to both odd and ...

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“…Chen and co‐workers also studied briefly the free‐radical vinyl polymerization of MLA, obtaining materials with properties similar to those reported ( M n = 180 kg mol −1 , T g ranging from 229 to 254 °C). [ 448 ] Copolymers with γ‐MMBL and dimethylene lactide were also prepared. Their attempts to perform the direct ROP of MLA were however unsuccessful, as the conjugated double bond is probably too reactive toward the catalysts used for this reaction.…”

Section: Polymerization Of (Meth)acrylic Monomers and Analogsmentioning

confidence: 99%

Production and Polymerization of Biobased Acrylates and Analogs

Fouilloux

Thomas

2021

Macromol. Rapid Commun.

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To prepare biobased polymers, particular attention must be paid to the obtention of the monomers from which they are derived. (Meth)acrylates and their analogs constitute such a class of monomers that have been extensively studied due to the wide range of polymers accessible from them. This review therefore aims to highlight the progresses made in the production and polymerization of (meth)acrylates and their analogs. Acrylic acid production from biomass is close to commercialization, as three different high‐potential intermediates are identified: glycerol, lactic acid, and 3‐hydroxypropionic acid. Biobased methacrylic acid is less common, but several promising options are available, such as the decarboxylation of itaconic acid or the dehydration of 2‐hydroxyisobutyric acid. Itaconic acid is also a vinylic monomer of great interest, and polymers derived from it have already found commercial applications. Methylene butyrolactones are promising monomers, obtained from bioresources via three different intermediates: levulinic, succinic, or itaconic acid. Although expensive, methylene butyrolactones have a strong potential for the production of high‐performance polymers. Finally, β‐substituted acrylic monomers, such as cinnamic, fumaric, muconic, or crotonic acid, are also examined, as they provide an original access to biobased materials from various renewable raw materials, such as protein waste, lignin, or wastewater.

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Polymerizability of Exo‐methylene‐lactide toward vinyl addition and ring opening

Cited by 22 publications

References 59 publications

Cross‐metathesis functionalized exo‐olefin derivatives of lactide

Cross‐metathesis functionalized exo‐olefin derivatives of lactide

Cyclopropenimine Superbases: Competitive Initiation Processes in Lactide Polymerization

Production and Polymerization of Biobased Acrylates and Analogs

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