Dehydrogenative Silylation of Terminal Alkynes with Hydrosilanes under Zinc–Pyridine Catalysis

Abstract

A combination of zinc triflate and pyridine in a nitrile medium was found to act as an effective catalytic system for dehydrogenative silylation with flexible pieces of terminal alkynes and hydrosilanes, thereby producing diverse alkynylsilanes in high to excellent yields.

Heterogeneous‐Gold‐Catalyzed Acceptorless Cross‐Dehydrogenative Coupling of Hydrosilanes and Isocyanic Acid Generated in situ from Urea

“…

Cross-coupling reactions (e.g., Suzuki, Negishi, Heck, Stille, Kumada, and Buchwald-Hartwig reactions) are of paramount importance and have proven useful for the design of molecules. [6] Quite recently, we have also reported C À N (terminal alkynes and amides), [7] P À N (H-phosphonates and amides), [8] SiÀN (hydrosilanes and indoles), [9] and SiÀC (hydrosilanes and terminal alkynes) [10] bond-forming reactions by cross-dehydrogenative coupling strategy. [1] Recently, cross-dehydrogenative coupling reactions by direct activation of CÀH or XÀH bonds have been emerging as synthetic tools because they are more atom efficient and environmentally benign than classical cross-coupling reactions.

…”

Tuning the Selectivity of AuPd Nanoalloys towards Selective Dehydrogenative Alkyne Silylation

“…Both systems operate under similar conditions at 80 °C in toluene, and O 2 was applied as the terminal oxidant. Despite these recent advances, there is room for improvement, because existing methods work at elevated temperatures (100–120 °C),–, require laborious preparation of the catalyst,, lead to hydrosilylation byproducts,– need high catalyst loadings, and most severely show low tolerance towards functional groups –,––. Therefore, new easily accessible and bench‐stable catalysts that work under mild conditions are demanded.…”

Zinc reagents as non-noble catalysts for alkyne activation

“…11 Later, Tsuchimoto and co-workers developed another protocol replacing silylation reagent 12 with alkylsilanes. 12 In addition, the preparation of alkynylstannanes was disclosed by Baba and coworkers. 13 The reaction required the use of Bu 3 SnOMe (15), with ZnBr 2 being the most effective catalyst.…”

“…The in situ generation of zinc acetylides was also exploited for the preparation of synthetically useful alkynylsilanes. Shaw and co-workers described a zinc-catalyzed silylation of terminal alkynes using TMSOTf (12) and Zn(OTf) 2 in the presence of an organic base under mild conditions (Scheme 2, a). 11 Later, Tsuchimoto and co-workers developed another protocol replacing silylation reagent 12 with alkylsilanes.…”