Palladium-Catalyzed Formylation of Aryl Halides with tert-Butyl Isocyanide

Abstract

A novel palladium-catalyzed formylation of aryl halides with isocyanide in the presence of Et3SiH has been demonstrated, which provides a strategy toward important aldehydes with moderate to excellent yield. The advantage of this reaction includes milder conditions, convenient operation, lower toxicity, and wide functional group tolerance.

An Efficient and General Method for Formylation of Aryl Bromides with CO2 and Poly(methylhydrosiloxane)

“…[9][10][11][12][13][14] For example, Manabe and co-workers [15] adopted Nformylsaccharin as ah ighly reactive CO surrogate and silane as ah ydrogen donor,a nd therebyr ealized reductivec arbonylation of aryl bromides to aryl aldehydes catalyzed by palladium acetate with the aid of al igand and ab ase (Scheme 1a). Subsequently,o ther CO surrogates, including isocyanide [16] and paraformaldehyde, [17] were successfully appliedi nt he carbonylation of aryl/hetaryl iodidesa nd bromides in the presence of different silanes, providing access to aw ide range of aryl/hetaryl aldehydes under relatively mild conditions (Scheme 1b, c). Although great progress has been made in the use of Pdcatalyzed CO-free carbonylation of aromatic halidest os ynthe-size aryl(hetaryl)a ldehydes, there are still inherentd rawbacks, such as the need for expensive CO surrogates and ligands, and inevitable by-product formation.…”

Cyanation of Anilines to Aryl Nitriles Using tert‐Butyl Isocyanide: A Simple and Copper‐free Procedure

“…In particular, isocyanides were found to be a powerful precursors in the work of multicomponent reaction, namely the Passerine and Ugi reactions. In recent years, isocyanides have been used as a cyano source for the construction of C─O, C─C, C─N bonds and aldehydes through the insertion of isocyanides into C–X bonds via palladium‐catalyzed reactions . Herein, we would like to report on the use of tert ‐butyl isocyanide as cyano source for the conversion of anilines to aryl nitriles (Figure ).…”

Selective and Efficient Formylation of Indoles (C3) and Pyrroles (C2) Using 2,4,6‐Trichloro‐1,3,5‐Triazine/Dimethylformamide (TCT/DMF) Mixed Reagent

“…Moreover, during the multistep synthesis of many natural products, formylation reaction is often necessary, and the selectivity, simplicity, and efficiency of this step are highly critical . Some of the widely used formylating agents that have been reported up to now are POCl 3 / N , N ‐dimethylformamide (DMF) , HCO 2 H/ N,N′ ‐Dicyclohexylcarbodiimide (DCC) , 2,2,2‐trifluoroethyl formate , formic acid/1‐Ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDAC) , acetic formic anhydride , formyl‐pivaloyl anhydride , cyanomethylformate , pentafluorophenyl formate , imidazole/DMF , MeOH/Ru , CO 2 /PhMe 2 SiH , AgOTf/Cl 2 CHOMe , tetramethylethylenediamine/O 2 /visible light , FeCl 3 /DMSO , CO/acid , 2‐benzotriazolyl‐1,3‐dioxolane , N ‐methyl aniline/Ru , Pd/CO/H 2 , tert ‐butyl isocyanide , Pd/CH 3 NO 2 , etc. In spite of the diversity of formylating agents, there are serious restrictions for the preparation of some of them, such as harsh experimental conditions, the use of unusual reagents, formation of unwanted or toxic byproducts, use of expensive procedures for their synthesis, and thermal instability of the reagents.…”