COF‐300, an imine‐linked, crystalline, and microporous covalent organic framework, modified by coordination of Pd(OAc)2 to its walls, afforded a hybrid material, Pd(OAc)2@COF‐300, which was used as an efficient heterogeneous catalyst for cross‐coupling reactions. This material showed excellent catalytic activity for the phosphine‐free Suzuki–Miyaura, Heck, and Sonogashira cross‐coupling reactions with low palladium loadings (0.1 mol % Pd). X‐ray photoelectron spectroscopy analysis of the catalyst after the reaction showed that PdII is converted to Pd0, which is trapped within the COFs nanopores. This was confirmed by high‐resolution transmission electron microscopy. Moreover, promising results were obtained using Pd(OAc)2@COF‐300 under continuous‐flow conditions for a Suzuki–Miyaura cross‐coupling reaction.

No abstract

A facile and efficient method for esterification and amidation of carboxylic acids under neutral conditions has been developed. Esters and amides can be prepared by reacting a carboxylic acid (1 mmol) with tribromoisocyanuric acid (0.37 mmol) and triphenylphosphine (1 mmol) in dichloromethane at room temperature, followed by addition of an alcohol or an amine, respectively.

Halogenation O 0235 Trihaloisocyanuric Acids as Convenient Reagents for Regioselective Halogenation of β-Dicarbonyl Compounds. -Regioselective mono-and dihalogenation of β-dicarbonyl compounds becomes possible with different amounts of trihaloisocyanuric acids. -(MENDONCA, G. F.; SINDRA, H. C.; DE ALMEIDA, L. S.; ESTEVES*, P. M.; DE MATTOS, M. C. S.; Tetrahedron Lett. 50 (2009) 4, 473-475; Dep. Quim.Org., Inst. Quim., Univ. Fed. Rio de Janeiro,