Asymmetric Synthesis of Silicon‐Stereogenic Vinylhydrosilanes by Cobalt‐Catalyzed Regio‐ and Enantioselective Alkyne Hydrosilylation with Dihydrosilanes

Abstract

The strategic carbon-to-silicon substitution at a stereogenic center can produce chiral silanes with significantly improved properties relative to their carbon congeners. We herein report an unprecedented cobalt-catalyzed asymmetric hydrosilylation of unsymmetric alkynes with dihydrosilanes that furnishes silicon-stereogenic vinylhydrosilanes with high regio- and enantioselectivity. The absolute configurations of the products were determined by chiroptical methods in combination with DFT calculations. The synthetic versatility of the vinylhydrosilanes as chiral building blocks was further demonstrated by asymmetric Si-H insertion and catalytic hydroboration reactions.

Recent Advances in Hydrometallation of Alkenes and Alkynes via the First Row Transition Metal Catalysis

“…[239] In 2018, Huang and co-workers developed a regio-and enantioselective alkyne hydrosilylation with a pybox-cobalt catalyst (101-CoCl 2 ), providing an efficient strategy for the preparation of silicon-stereogenic vinylhydrosilanes (Scheme 86). [239] In 2018, Huang and co-workers developed a regio-and enantioselective alkyne hydrosilylation with a pybox-cobalt catalyst (101-CoCl 2 ), providing an efficient strategy for the preparation of silicon-stereogenic vinylhydrosilanes (Scheme 86).…”

Cobalt(II) and (I) Complexes of Diphosphine‐Ketone Ligands: Catalytic Activity in Hydrosilylation Reactions

“…The scope for the unsaturated substrate is versatile, including alkene,, , alkyne, carbonyl, and carboxylic derivative groups. Additionally, a number of different silanes can be used: much research is performed with phenylsilane, and other silanes such as diphenylsilane, alkyl silanes, and alkoxy silanes, can be employed as well.…”

External Electric Field—Phenyl interaction boosts hydrosilylation of substituted alkynes to α‐vinylsilane

“…However, control of stereo‐ and regioselectivity is the major issue hampering the widespread use of this method, largely because three possible hydrosilylation products, namely α‐, β‐(Z)‐, and β‐(E)‐vinylsilanes, can be generated in the hydrosilylation reaction of terminal alkynes, with the former being rarely obtained selectively . By now, some works about the formation of α‐vinylsilane had been published by theorists and experimenters . By inspection of these researches, we found that the metal‐catalysts were mainly introduced for catalyzing this hydrosilylation of alkynes, such as Co, Pt, and Ru .…”

“…Vinylsilanes are valuable building blocks in organic synthesis and material chemistry because of their versatile characters, such as low toxicity, high stability, facile manipulations, and a variety of transformations . Accordingly, methods for the preparation of vinylsilanes have gained increased attentions from synthetic chemists, in which the hydrosilylation of alkynes was considered as a simple and straightforward method . This hydrosilylation reaction involves the addition of a Si − H bond across a C − C triple bond, bringing an atom‐economical result with 100% atom efficiency.…”

“…[65][66][67] By now, some works about the formation of α-vinylsilane had been published by theorists [39,40] and experimenters. [41][42][43][44][45][46][47][48][49] By inspection of these researches, we found that the metal-catalysts were mainly introduced for catalyzing this hydrosilylation of alkynes, such as Co, [41][42][43][44][45][46] Pt, [47] and Ru. [40,48,49] It is also known that the usage of metal-catalysts would inevitably refer to the questions of the preparation of various ligands and separation of extraneous catalyst, which not only caused much cost, but also the process complexity.…”