First Example of the Use of Biosourced Alkyl Levulinates as Solvents for Synthetic Chemistry: Application to the Heterogeneously Catalyzed Heck Coupling

Abstract

Modern organic synthesis is highly demanding for environmentally friendly biosourced solvents. In this area, alkyl levulinates, that can be obtained directly from lignocellulose, represent serious candidates. This was demonstrated for the first time in this study, using Heck C−C coupling in the presence of various heterogeneous Pd‐catalysts. In most cases quantitative conversions of aryl halides were observed within short reaction time, associated with good to high isolated yields (30‐95%). In addition to be suitable solvents for this application, alkyl levulinates can be recovered and reused, offering when associated to heterogeneous catalysts facile work‐up procedure for easy obtaining of pure products.

A Landscape of Lignocellulosic Biopolymer Transformations into Valuable Molecules by Heterogeneous Catalysis in C’Durable Team at IRCELYON

“…Here, n-butyl levulinate showed to be as suitable as GVL or organic solvents for Heck C-C coupling, even in the presence of a heterogeneous catalyst. The system solvent/catalyst has shown to be completely recoverable and reusable compiling many requirements for a green synthetic route (Scheme 6) [76]. Scheme 6.…”

“…completely recoverable and reusable compiling many requirements for a green synthetic route (Scheme 6) [76]. Scheme 6.…”

Contribution to the production and use of biomass-derived solvents – a review

“…In addition, Ferrer et al [105] presented in their patent of the use of alkyl levulinates for metallic surface degreasing some data showing that butyl, iso-butyl and pentyl levulinates present excellent environment, health and safety properties, such as not being cytotoxic neither mutagenic. Marcel et al [96] performed the use of alkyl levulinates (methyl, ethyl and n-butyl) as solvents for the heterogeneously Pd-catalyzed Heck coupling, as far as it is known, for the first time. The reaction of Heck coupling between 2-iodoanisole and n-butylacrylate giving 2-methoxycinnamic acid butyl ester using alkyl levulinates as solvents showed yields ranging from 88 to 98%.…”

Evaluation of the toxicity profiles of three families of solvents from biomass: levulinate, lactate and furfural derivatives

“…These solvents are obtained from sustainable sources, such as glucose, sucrose, or lignocellulose, by enzymatic processes, esterification, fermentation, 3 or catalysis, [4][5][6] making their use interesting when ecosustainability is a goal. All this has led to a wide and varying range of applications, highlighting their use as antimicrobial agents, 7 food additives, flavoring agents, 8,9 precursors for environmentally friendly plasticizers, 10 adjuvants in transdermal pharmaceuticals, 11 precursors for biologically active natural products, 12 precursors and intermediates in drug synthesis, 8,13 or even as a green solvent in different processes, [14][15][16] among others. In recent years, due to their associated green properties, they have even been used as components of other green solvents such as deep eutectic solvents, further broadening the scope of their applications.…”