γ-Valerolactone as an alternative biomass-derived medium for the Sonogashira reaction

Abstract

γ-Valerolactone (GVL) can be used as an efficient and practical alternative to the banned and commonly used dipolar aprotic solvents.

Definition of green synthetic tools based on safer reaction media, heterogeneous catalysis, and flow technology

“…With a similar approach we have showed that similar results can be obtained by using GVL as medium for Pd/C catalyzed Sonogashira-Hagihara reaction [35] and in the the Hiyama reaction [36].…”

Scope and limitations of a DMF bio-alternative within Sonogashira cross-coupling and Cacchi-type annulation

“…In addition to its renewability, Cyrene, as yet, has no associated pernicious effects and could potentially represent a direct and functional replacement in many of the fundamental reactions that typically employ DMF [31–32]. The replacement of solvents with regulatory issues with bio-derived alternatives has provided a series of advances within the cross-coupling arena [33], allowing efficient C–C bond formation via cornerstone Pd-based methods including Suzuki–Miyaura [34–35], Mizoroki–Heck [36–37], Sonogashira [38], Stille [39], Hiyama reactions [40], and hydroformylation reactions [41]. …”

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

“…This indicates a low influence of the nature (activated or not) of the aryl halide in BuLev. Although some successful examples with non‐activated or deactivated substrates are found in previous studies concerning C−C couplings in biosourced solvents, this specific aspect of reactivity was not clearly highlighted ,,…”

“…Vaccaro and co. have demonstrated for the first time the suitability of GVL for C−C cross‐coupling like Sonogashira and Heck reactions. In the presence of heterogeneous Pd catalysts, they particularly noticed a reduction of Pd leaching during the course of the reaction as an advantage of GVL over usual NMP or DMF solvents ,. As shown in Figure , 2‐MeTHF and GVL can be produced in several steps from lignocellulosic biomass necessitating notably a catalytic (direct or transfer) hydrogenation.…”