0000000000134036
AUTHOR
Giacomo Strappaveccia
showing 3 related works from this author
An E-Factor Minimized Protocol for a Sustainable and Efficient Heck Reaction in Flow
2014
A highly sustainable and waste-minimized protocol for Heck coupling has been defined. Optimal conditions have been defined by exploiting a heterogeneous catalyst based on supported ionic liquid-like phases featuring high Pd loading (10 wt %) and by optimizing its efficiency in a recoverable green reaction medium (acetonitrile/water azeotrope). Pure products 4a–l and 6a–h have been isolated chromatography-free in high yields (74–99%) and with extremely low environmental factor (E-factor) values (2.3–5.0). With the application of flow technology, the selected heterogeneous base and Pd catalyst have been fully recovered and reused, and minimum palladium leaching allowed for isolation of the fi…
Sustainable Approach to Waste-Minimized Sonogashira Cross-Coupling Reaction Based on Recoverable/Reusable Heterogeneous Catalytic/Base System and Ace…
2016
In this contribution, we present a chemically efficient and sustainable protocol for the palladium-catalyzed copper-free Sonogashira cross-coupling reaction, based on the use of a heterogeneous catalytic system. This consists in the combination of a palladium catalyst on highly cross-linked thiazolidine network on silica and a polystyrene-supported base. The solid catalyst/base system acts as a palladium scavenger avoiding leaching of the metal and consequent product contamination. The reaction can be conducted in safe and easily recoverable acetonitrile/water azeotrope as reaction medium. This proved to be an efficient greener alternative to the classic toxic aprotic media commonly used in…
Evidences of release and catch mechanism in the Heck reaction catalyzed by palladium immobilized on highly cross-linked-supported imidazolium salts
2014
Abstract Palladium (10 wt%) on a highly cross-linked imidazolium-based material was used as catalyst in 0.1 mol% in the Heck reaction between several alkenes and aryl iodides. Products were obtained from good to high yields. Deeper investigations showed a release of Pd species in solution and their capture by the imidazolium-based support. When a sixfold amount of support was employed the re-captured Pd species (0.5–0.6 wt%) were not anymore catalytically active. This result represents a new interesting aspect of this work since the highly cross-linked imidazolium-based material can act also as Pd scavenger avoiding the release of the metal in solution. Important differences between Heck an…