Preparation of functional styrenes from biosourced carboxylic acids by copper catalyzed decarboxylation in PEG

Abstract

A general protocol for the copper-catalyzed decarboxylation of α,β-unsaturated carboxylic acids in PEG, particularly of biosourced cinnamic acid analogues, is reported. Moderate to high isolated yields (31-96%) towards the styrene derivatives were obtained. For the first time, decarboxylation of α-amino acids to the corresponding amines was successfully performed with good to high yields and extended to the decarboxylation of a few condensed heterocyclic compounds. Both the use of PEG as a green solvent and direct separation of the pure product of the reaction by distillation permitted the reuse of the solvent and the Cu-based catalytic system over several cycles without deactivation. This was extended to the synthesis of 4-vinylguaiacol on the laboratory scale in an average 92% yield. † Electronic supplementary information (ESI) available. See

Bio‐based vinylphenol family: Synthesis via decarboxylation of naturally occurring cinnamic acids and living radical polymerization for functionalized polystyrenes

“…These results suggest that the o ‐ and p ‐hydroxy groups work efficiently for the simple base‐induced decarboxylation of cinnamic acids due to the resonance effects. However, decarboxylation of m ‐coumaric acid into m ‐hydroxystyrene (3VP) was successfully achieved by the other common method using a copper catalyst …”

Organocatalytic Decarboxylation of Amino Acids as a Route to Bio‐based Amines and Amides

“…However, acetophenone itself was partially consumed by transamination to 1phenethylamine (entry 25). α,β-Unsaturated ketones (entries [14][15][16][17][18][19][20][21][22][23][24], in particular the derivatives of 2-cyclohexen-1-one (entries 18-21 and 23), are among the most active organocatalysts: for instance, 2 a was produced in > 85 % yield within 4 h by using isophorone or 3-phenyl-2-cyclohexen-1-one. These catalysts increased the amine yield at least by a factor 10 compared to the thermal reaction.…”

“…The non‐oxidative decarboxylation of amino acids is catalysed by homogeneous transition metal complexes, such as Cu I ‐phenanthroline . However, this method involves high catalyst loadings (10 mol%) and proceeds at high temperature (>180 °C).…”

“…[15,16] The non-oxidative decarboxylation of amino acids is catalysed by homogeneous transition metal complexes, such as Cu Iphenanthroline. [17] However, this method involves high catalyst loadings (10 mol%) and proceeds at high temperature (> 180°C). Moreover, the scope is limited to amino acids with aliphatic and aromatic side chains, from which the corresponding primary amines are isolated only in moderate yield (up to 68 %).…”

Thin‐film nanostructure and polymer architecture in semicrystalline syndiotactic poly(p‐methylstyrene)–(cis‐1,4‐polybutadiene) multiblock copolymers

“…Random stereo‐irregular copolymers of styrene (S) with 1,3‐butadiene (B) (styrene–butadiene–rubber) are by far the most commercially important commodity polymers of these monomers, produced in amounts of the order of 5.3 million tons in 2014 via emulsion or solution processes; these copolymers find applications as adhesives and sealants, and in gasket and tyre production . To face environmental concerns and make their production more sustainable, the drop‐in synthesis of B and S is emerging to satisfy the increasing demand for these monomers and to replace the petrochemical/natural feedstocks with renewable sources. More interestingly diblock copolymers of S with B and high‐impact polystyrene can produce micro‐ and nanophase separated morphologies where the glassy polystyrene (PS) acts as a reversible physical crosslink in the flexible rubber phase of poly(1,3‐butadiene) (PB) .…”