Catalytic Decarboxylation of Silyl Alkynoates to Alkynylsilanes

Carboxylate-Catalyzed C-Silylation of Terminal Alkynes

A carboxylate-catalyzed, metal-free C-silylation protocol for terminal alkynes is reported using a quaternary ammonium pivalate as the catalyst and commercially available N,O-bis(silyl)acetamides as silylating agents. The reaction proceeds under mild conditions, tolerates a range of functionalities, and enables concomitant O- or N-silylation of acidic OH or NH groups. A Hammett ρ value of +1.4 ± 0.1 obtained for para-substituted 2-arylalkynes is consistent with the proposed catalytic cycle involving a turnover-determining deprotonation step.

Photocatalytic Alkynylation of Hydrosilanes via Hydrogen Atom Transfer

Alkynylsilanes are significant structural units frequently used in synthetic chemistry, medicinal chemistry, functional materials, and life sciences. Herein, we report a method for using a hydrogen atom transfer (HAT) strategy in combination with visible-light-driven photocatalysis to achieve a direct coupling reaction between benzene sulfonyl acetylene and tertiary silanes, and a diverse alkynylation of hydrosilanes in the presence of reactive groups was achieved with this strategy. It is important to note that dihydroalkyl/aryl silanes are also suitable for the protocol of HAT photocatalytic of 4CzIPN and quinuclidine.

Cobalt-Catalyzed Dehydrogenative C-H Silylation of Alkynylsilanes

Herein, we report that a cobalt catalyst permits the general synthesis of substituted alkynylsilanes through dehydrogenative coupling of alkynylsilanes and hydrosilanes. Several silylated alkynes, including di- and trisubstituted ones, were prepared in a one-step procedure. Thirty-seven compounds were synthesized for the first time by applying our catalyst system. The alkynylsilanes bearing hydrosilyl moieties provide an opportunity for further functionalization (e. g., hydrosilylation). The use of primary silanes as substrates and precatalyst activators permits the use of inexpensive and easily accessible 3d metal precatalysts, and avoids the presence of additional activators.

Photochemical alknylation of hydrosilanes by iron catalysis

Alkynylsilanes is one kind of essential synthetic block in organic chemistry. The established synthetic routes remain some drawbacks regarding to harsh reaction conditions or expensive/rare metal catalyst. Herein, we report...

Fluoride Ion-Initiated Decarboxylation of Silyl Alkynoates to Alkynylsilanes

This communication describes the development of a metal-free catalytic decarboxylation of silyl alkynoates to alkynylsilanes. Treatment of a silyl alkynoate with a catalytic amount of tetrabutylammonium difluorotriphenylsilicate (TBAT) in N,N-dimethylformamide at 150 °C resulted in decarboxylation to give the corresponding alkynylsilane in good to excellent yield (75 → 95%). The TBAT system was applicable to the decarboxylation of sterically demanding silyl alkynoates such as tert-butyldiphenylsilyl 3-phenylpropiolate. Mechanistic studies revealed that the tetrabutylammonium alkynoate derived from TBAT and the silyl alkynoate act as a catalyst for the decarboxylation.