B(C₆F₅)₃/Amine‐Catalyzed C(sp)−H Silylation of Terminal Alkynes with Hydrosilanes: Experimental and Theoretical Studies

Abstract

Transition metal catalyzed C−H functionalization of organic compounds has proved to be a useful atom‐efficient strategy in organic synthesis. In contrast, main‐group‐element‐based catalytic processes for C−H functionalization have remained underexplored to date. Reported herein is the catalytic C(sp)−H silylation of a wide range of terminal alkynes with hydrosilanes by using a combination of B(C6F5)3 and an organic base such as triethylenediamine (DABCO). This protocol constitutes the first example of boron‐catalyzed C(sp)−H functionalization, offering a convenient route for the synthesis of a variety of alkynylsilanes. Experimental and computational studies have revealed that DABCO plays two crucial roles (Lewis base and Brønsted base) in this catalytic transformation.

Synthesis of substituted quinolines via B(C6F5)3‐catalyzed aniline‐aldehyde‐pyruvate oxidative annulation

“…Based on our findings and the related references, a plausible reaction mechanism for the present B(C 6 F 5 ) 3 ‐catalyzed aniline‐aldehyde‐pyruvate annulation reaction is depicted in Scheme . Upon heating, B(C 6 F 5 ) 3 is generated from a Lewis adduct or the hydroxy borate to activate the imine I derived from aniline 1a and aldehyde 2a , which then undergoes nucleophilic…”

“…B(C 6 F 5 ) 3 , reported in 1964, re‐emerged as a paradigm for small molecule activation in the past decade, especially as a component in frustrated Lewis pairs (FLPs) chemistry . Moreover, B(C 6 F 5 ) 3 has been successfully employed in various other transformations . One of the research hotspots is the borane‐catalyzed multicomponent reactions (MCRs).…”

B(C6F5)3-catalyzed dehydrogenative cyclization of N-tosylhydrazones and anilines via a Lewis adduct: a combined experimental and computational investigation

“…65 In sum, the computational results do have concurrence with the experimental ndings, particularly in understanding the dual role of B(C 6 F 5 ) 3 in activating the N-tosylhydrazone towards nucleophilic attack and acceptor-less liberation of H 2 with the formation of a FLP (Scheme 9). Additionally, the rate determining step involving intramolecular proton transfer (7 ba / 8 ba ; D ‡ G L S ¼ 32.0 kcal mol À1 ) can be surmounted at a reaction temperature of 80 C. 66 Optimized geometries of the transition states with selected geometrical parameters along with the energy proles are shown in Fig. 1.…”

Tuning the Selectivity of AuPd Nanoalloys towards Selective Dehydrogenative Alkyne Silylation

“…Recently, Ma et al. described the CDC between terminal alkynes and di‐ or trihydrosilanes by using B(C 6 F 5 ) 3 /DABCO as an organic catalyst system …”