Nickel-Catalyzed Decarbonylative Alkylation of Aroyl Fluorides Assisted by Lewis-Acidic Organoboranes

Abstract

Herein, nickel-catalyzed decarbonylative C–F bond alkylation of aroyl fluorides with organoboron reagents is reported. Aroyl fluorides are more chemically stable than the corresponding aroyl chlorides and can be readily synthesized from the corresponding carboxylic acids. The fluoronickel intermediate formed via oxidative addition interacts with Lewis-acidic trialkylboranes, and the subsequent decarbonylative alkylation proceeds. This new synthetic methodology allows 1,2-bifunctionalization of aromatic carboxylic acids via palladium-catalyzed ortho -C–H arylation. In addition, an unprecedented 1,4-nickel migration on ortho -arylated aroyl fluorides was observed. As a demonstration of the synthetic utility of the present reaction, the sequential 1-alkyl-2-arylation of 3-hydroxy-2-naphthoic acid was accomplished via chemoselective alkylation at a fluorocarbonyl moiety and the subsequent C–O bond arylation at an acetoxy group.

Acid Fluorides in Transition‐Metal Catalysis: A Good Balance between Stability and Reactivity

“…[14] Soon after, the same group reported an ickel-catalyzed decarbonylative borylation of acid fluorides 4 (Scheme 5). As imilar strategy has been used for the decarbonylative methylation or ethylation of acid fluoride using Lewis acidic trimethyl-or triethylborane and ac losely related catalytic system (Ni(cod) 2 /dppe), which suffers from anarrower scope.…”

Catalytic C−H/C−F Coupling of Azoles and Acyl Fluorides

“…Transition‐metal‐catalyzed cross‐coupling reactions of acyl electrophiles with aryl nucleophiles represent a powerful and reliable synthetic strategy for the introduction of acyl fragments into aromatic rings to provide aromatic ketones, and a large variety of carboxylic acid derivatives are currently used as acyl electrophiles . Among these, acyl fluorides have recently gained much attention as valuable carbon‐based electrophiles in cross‐coupling reactions, especially in acyl coupling and decarbonylative coupling reactions . Due to the moderate electrophilicity of acyl fluorides, they exhibit a good balance between stability and reactivity with respect to their compatibility under nucleophilic conditions, that is, they are more stable than the commonly employed acyl chlorides, yet more reactive than the corresponding esters and amides .…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Amongt hese, acyl fluorides have recently gained much attention as valuablec arbon-based electrophiles in cross-couplingreactions, especially in acyl coupling [14][15][16][17] and decarbonylative coupling reactions. [17][18][19][20][21][22] Due to the moderate electrophilicity of acyl fluorides,t hey exhibit ag ood balance between stability and reactivity with respectt ot heir compatibility under nucleophilic conditions, that is, they are more stable than the commonly employed acyl chlorides, [4] yet more reactive than the corresponding esters [9, 13b] and amides. [5-9, 11,13e] In fact, acyl fluorides are isolable using column chromatography on silica gel andc an be used without any special precautions against moisture.…”

Synthesis of Arylstannanes via Palladium‐Catalyzed Decarbonylative Coupling of Aroyl Fluorides

“…With the optimized condition in hand (entry 16 in Table ), the substrate scope was surveyed (Scheme ). Acyl fluorides were readily prepared from the corresponding carboxylic acids or acyl chlorides . It was found that acyl fluorides with an extended‐conjugated system ( 1 a , c , d ) reacted without difficulty, providing stannylation products in 77–89% isolated yields.…”