2983-65-5Relevant articles and documents
Enzymatic Specific Production and Chemical Functionalization of Phenylpropanone Platform Monomers from Lignin
Ohta, Yukari,Hasegawa, Ryoichi,Kurosawa, Kanako,Maeda, Allyn H.,Koizumi, Toshio,Nishimura, Hiroshi,Okada, Hitomi,Qu, Chen,Saito, Kaori,Watanabe, Takashi,Hatada, Yuji
, p. 425 - 433 (2017)
Enzymatic catalysis is an ecofriendly strategy for the production of high-value low-molecular-weight aromatic compounds from lignin. Although well-definable aromatic monomers have been obtained from synthetic lignin-model dimers, enzymatic-selective synthesis of platform monomers from natural lignin has not been accomplished. In this study, we successfully achieved highly specific synthesis of aromatic monomers with a phenylpropane structure directly from natural lignin using a cascade reaction of β-O-4-cleaving bacterial enzymes in one pot. Guaiacylhydroxylpropanone (GHP) and the GHP/syringylhydroxylpropanone (SHP) mixture are exclusive monomers from lignin isolated from softwood (Cryptomeria japonica) and hardwood (Eucalyptus globulus). The intermediate products in the enzymatic reactions show the capacity to accommodate highly heterologous substrates at the substrate-binding sites of the enzymes. To demonstrate the applicability of GHP as a platform chemical for bio-based industries, we chemically generate value-added GHP derivatives for bio-based polymers. Together with these chemical conversions for the valorization of lignin-derived phenylpropanone monomers, the specific and enzymatic production of the monomers directly from natural lignin is expected to provide a new stream in “white biotechnology” for sustainable biorefineries.
Visible-Light-Driven Cleavage of C?O Linkage for Lignin Valorization to Functionalized Aromatics
Lin, Jinchi,Wu, Xuejiao,Xie, Shunji,Chen, Liangyi,Zhang, Qinghong,Deng, Weiping,Wang, Ye
, p. 5023 - 5031 (2019/12/02)
Lignin is the most abundant source of renewable aromatics. Catalytic valorization of lignin into functionalized aromatics is attractive but challenging. Photocatalysis is a promising sustainable approach. The strategies for designing well-performing photocatalysts are desired but remain limited. Herein, a facile energy band engineering strategy for promoting the photocatalytic activity of zinc–indium–sulfide (ZnmIn2Sm+3) for cleavage of the lignol β-O-4 bond under mild conditions was developed. The energy band structure of ZnmIn2Sm+3 could be tuned by controlling the atomic ratio of Zn/In. It was found that Zn4In2S7 performed best for cleavage of the β-O-4 bond under visible-light irradiation, owing to its appropriate energy band structure for offering adequate visible-light absorption and suitable redox capability. Functionalized aromatic monomers with near 18.4 wt % yield could be obtained from organosolv birch lignin. Mechanistic studies revealed that the β-O-4 bond was efficiently cleaved mainly through a one-step redox-neutral pathway via a Cα radical intermediate. The thiol groups on the surface of Zn4In2S7 played a key role in cleavage of the β-O-4 bond.
Rh-Catalyzed Decarbonylative Addition of Salicylaldehydes with Vinyl Ketones: Synthesis of Taccabulins A–E
Rao, Maddali L. N.,Ramakrishna, Boddu S.
, p. 7545 - 7554 (2019/12/15)
A rhodium-catalyzed decarbonylative addition of salicylaldehydes with vinyl ketones was developed to synthesize o-hydroxydihydrochalcones (2-hydroxyphenethyl ketones). These decarbonylative addition reactions afforded various functionalized o-hydroxydihydrochalcones in moderate to good yields with broad functional group tolerance and selectivity. This method was also applied further in the divergent synthesis of dihydrochalcone derived taccabulins A–E.
A short and efficient total synthesis of ficuseptamines A and B
Hassan, Hani Mutlak A.
, (2018/08/24)
A rapid and efficient total synthesis of ficuseptamines A and B by a cross metathesis strategy is described.
Synthesis of the natural product descurainolide and cyclic peptides from lignin-derived aromatics
Ojo, O. Stephen,Nardone, Brunello,Musolino, Stefania F.,Neal, Andrew R.,Wilson, Liam,Lebl, Tomas,Slawin, Alexandra M. Z.,Cordes, David B.,Taylor, James E.,Naismith, James H.,Smith, Andrew D.,Westwood, Nicholas J.
supporting information, p. 266 - 273 (2018/01/17)
Alternative sources of potential feedstock chemicals are of increasing importance as the availability of oil decreases. The biopolymer lignin is viewed as a source of useful mono-aromatic compounds as exemplified by the industrial scale production of vanillin from this biomass. Alternative lignin-derived aromatics are available in pure form but to date examples of the use of these types of compounds are rare. Here we address this issue by reporting the conversion of an aromatic keto-alcohol to the anti- and syn-isomers of Descurainolide A. The key step involves a rhodium-catalyzed allylic substitution reaction. Enantio-enriched allylic alcohols were generated via an isothiourea-catalyzed kinetic resolution enabling access to both the (2R,3R) and (2S,3S) enantiomers of anti-Descurainolide A. In addition we show that the lignin-derived keto-alcohols can be converted into unnatural amino acid derivatives of tyrosine. Finally, these amino acids were incorporated into cyclic peptide scaffolds through the use of both chemical and an enzyme-mediated macrocylisation.
Degradation of β-O-4 model lignin species by vanadium Schiff-base catalysts: Influence of catalyst structure and reaction conditions on activity and selectivity
Parker, Heather J.,Chuck, Christopher J.,Woodman, Timothy,Jones, Matthew D.
, p. 40 - 47 (2016/05/10)
In the pursuit of value-added products from the degradation of the abundant aromatic biopolymer lignin, homogeneous catalysis has the potential to provide a mild, selective route to monomeric phenols. Homogeneous vanadium catalysts have previously been shown to effectively cleave dimeric β-O-4 model lignin compounds, with selectivity for C-C or C-O cleavage, or benzylic oxidation, depending on the ligand structure and oxidation state of the metal. In this study, a systematic kinetic investigation was undertaken in order to gain further understanding of the role of ligand structure and reaction conditions on the activity of vanadium Schiff-base catalysts towards a non-phenolic β-O-4 model lignin dimer, and the selectivity of these species towards C-O bond cleavage. Catalytic activity was found to be increased by the addition of bulky, alkyl substituents at the 3′-position of the phenolate ring, whereas electron-withdrawing substituents were found to dramatically reduce activity irrespective of their size. Selective depolymerization of a phenolic β-O-4 dimer was also achieved.
Metallo-deuteroporphyrin as a biomimetic catalyst for the catalytic oxidation of lignin to aromatics
Zhu, Chenjie,Ding, Weiwei,Shen, Tao,Tang, Chenglun,Sun, Chenguo,Xu, Shichao,Chen, Yong,Wu, Jinglan,Ying, Hanjie
, p. 1768 - 1778 (2015/06/08)
A series of metallo-deuteroporphyrins derived from hemin were prepared as models of the cytochrome P450 enzyme. With the aid of the highly active CoII deuteroporphyrin complex, the catalytic oxidation system was applied for the oxidation of several lignin model compounds, and high yields of monomeric products were obtained under mild reaction conditions. It was found that the modified cobalt deuteroporphyrin that has no substituents at the meso sites but does have the disulfide linkage in the propionate side chains at the β sites exhibited much higher activity and stability than the synthetic tetraphenylporphyrin. The changes in the propionate side chains can divert the reactivity of cobalt deuteroporphyrins from the typical C-C bond cleavage to C-O bond cleavage. Furthermore, this novel oxidative system can convert enzymolysis lignin into depolymerized products including a significant portion of well-defined aromatic monomers.
DEPOLYMERIZATION OF LIGNIN USING SOLID ACID CATALYSTS
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Page/Page column 6; 7, (2012/12/13)
The invention provides for a process for the depolymerization of lignin in an inert atmosphere to result in substituted phenolic monomer compounds. The process is catalysed by heterogeneous solid acid catalysts and is carried out in batch or continuous mode.
CATALYTIC DISPROPORTIONATION AND CATALYTIC REDUCTION OF CARBON-CARBON AND CARBON-OXYGEN BONDS OF LIGNIN AND OTHER ORGANIC SUBSTRATES
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Page/Page column 105-106, (2011/02/24)
The present invention provides methods and catalyst compositions for the catalytic reduction of carbon-oxygen bonds of organic substrates and the catalytic disproportionation of carbon-oxygen or carbon-carbon bonds of organic substrates. These methods and catalyst compositions may be used to depolymerize lignin. The disproportionation of carbon-oxygen or carbon-carbon bonds of organic substrates or lignin is carried out by cleaving a carbon-oxygen bond or a carbon-carbon bond in a catalytic disproportionation reaction. The catalysts may be formed from a metal precursor such as ruthenium or vanadium and a bidentate ligand The catalytic reduction of carbon-oxygen bonds of organic substrates such as lignin is carried out by cleaving a carbon-oxygen bond in the presence of a hydrogen atom source. Lignin fragments produced following depolymerization by such methods may be further processed into fuels.
Non-oxidative vanadium-catalyzed co bond cleavage: Application to degradation of lignin model compounds
Son, Sunghee,Toste, F. Dean
supporting information; experimental part, p. 3791 - 3794 (2010/08/22)
(Chemical Equation Presented) New direction: Changes In the ligand structure divert the reactivity of vanadium (V) oxo complexes from alcohol oxidation to a novel non-oxidative C-O bond cleavage. Thus, highly functionalized aryl enones can be selectively generated from lignin model compounds by vanadium-catalyzed cleavage of the β-O-4 linkage (see scheme; N blue, O red).
