Palladium-catalyzed addition of acylsilanes across alkynesviathe activation of a C–Si bond

Abstract

Palladium-catalyzed addition of a C–Si bond in acylsilanes across the triple bonds in an alkyne bearing a carbonyl group at one terminal is reported. The reaction proceeds with excellent regioselectivity,...

Palladium-Catalyzed Addition of Trifluoroacetylsilanes to Alkenes and Allenes via the Cleavage of C–Si Bonds

“…In an early study, Narasaka and co-workers reported on the palladium-catalyzed decarbonylative bis-silylation of electron-deficient alkenes or alkynes using a bis-silyl ketone, a reaction that likely proceeds through the oxidative addition process . We previously reported on the palladium-catalyzed addition of a C–Si bond in acylsilanes across allenes and alkynes . (Scheme A).…”

“…The reaction proceeded with complete regioselectivity, where a silyl group is incorporated into the central carbon of the allene moiety while an acyl group is attached to the internal position. The observed regioselectivity is identical to that observed for reactions using nonfluorinated acylsilanes . Monosubstituted allenes, including those bearing alkyl groups (i.e., 5a and 5b ), chlorides (i.e., 5c ), esters (i.e., 5d ) and imides (i.e., 5e ), successfully participated in this silylacylation reaction, providing the corresponding products in a regioselective manner.…”

“…We next examined the use of trifluoroacetylsilanes in the silylacylation of allenes. As a result of optimization based on our previous studies regarding the palladium-catalyzed silylacylation using acylsilanes (see SI for details), trifluoroacetylsilanes could be successfully added to a wide range of allenes when a Pd/PCy 3 catalyst was used (Scheme ). The reaction proceeded with complete regioselectivity, where a silyl group is incorporated into the central carbon of the allene moiety while an acyl group is attached to the internal position.…”