Palladium/Copper-Cocatalyzed Arylsilylation of Internal Alkynes with Acyl Fluorides and Silylboranes: Synthesis of Tetrasubstituted Alkenylsilanes by Three-Component Coupling Reaction

Abstract

In this Letter, the palladium/copper-cocatalyzed arylsilylation of internal alkynes with acyl fluorides and silylboranes is described. This is the first example in which acyl fluorides have been utilized for the three-component coupling reaction via decarbonylation, yielding a variety of tetrasubstituted alkenylsilanes in moderate to good yields.

Formation, Characterization, and Reactivity of Acyl Palladium Complexes in Pd(OAc)2/PCy3-Catalyzed Transformation of Acyl Fluorides

“…In the last decades, the utility of acyl fluorides has gained attention as an alternative carbon electrophile surrogate. They are easy-to-handle and suitably reactive synthetic materials among carboxylic acid derivatives that demonstrate moderate levels of electrophilicity and stability. , In the presence of appropriate transition-metal catalysts such as nickel or palladium, acyl fluorides function as an acyl, an aryl, or a fluorine , source, which imparts the potential to be utilized as not only a carbon electrophile, akin to other carboxylic acids, but also as a stable organic fluorination reagent. This type of utility has resulted in rapid development of transition metal-catalyzed transformations of acyl fluorides in recent years.…”

Recent Advances in C–F Bond Activation of Acyl Fluorides Directed toward Catalytic Transformation by Transition Metals, N-Heterocyclic Carbenes, or Phosphines

“…In addition to the described palladium-catalyzed bimolecular decarbonylative coupling of acyl fluorides, we have very recently reported an unprecedented three-component decarbonylative coupling of acyl fluorides with internal alkynes and silylboranes in a synergistic Pd/Cu bicatalytic system, yielding a wide variety of tetrasubstituted alkenylsilanes with good stereoselectivity (Scheme 28). 59 This protocol proved that acyl fluorides, with their excellent functional-group tolerance, can serve as alternatives to aryl halides as electrophiles. Based on various reference results, a possible reaction mechanism has been proposed as follows.…”

Nickel-Catalyzed Decarbonylative Reductive Alkylation of Aroyl Fluorides with Alkyl Bromides

“…Acyl fluorides are attractive building blocks because they are readily available from naturally abundant carboxylic acids and exhibit superior performance in transition-metal-catalyzed cross-coupling reactions. Since Schoenebeck disclosed the palladium-catalyzed decarbonylative trifluoromethylation of acyl fluorides in 2018, a large number of methodologies utilizing acyl fluorides as coupling partners via decarbonylation have been reported. , Thereby, the use of acyl fluorides as a viable alternative to aryl halides has been established. As part of our research on the application of acyl fluorides as electrophiles for the construction of C­( sp 2 )–C­( sp 3 ) bonds, we reported the nickel-catalyzed decarbonylative methylation/ethylation of acyl fluorides (Scheme a) .…”