Rhodium hydride enabled enantioselective intermolecular C\u2013H silylation to access acyclic stereogenic Si\u2013H

Kun An,Li-Chuan Liu,Guiyu Guan,Wenpeng Ma,Qing-Wei Zhang,Tao He,Wei He

doi:10.1038/s41467-022-28439-w

Kun An, Li-Chuan Liu + Show 5 more

Open Access

https://doi.org/10.1038/s41467-022-28439-w

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Abstract

The tremendous success of stereogenic carbon compounds has never ceased to inspire researchers to explore the potentials of stereogenic silicon compounds. Intermolecular C–H silylation thus represents the most versatile and straightforward strategy to construct C–Si bonds, however, its enantioselective variant has been scarcely reported to date. Herein we report a protocol that allows for the enantioselective intermolecular C–H bond silylation, leading to the construction of a wide array of acyclic stereogenic Si–H compounds under simple and mild reaction conditions. Key to the success is (1) a substrate design that prevents the self-reaction of prochiral silane and (2) the employment of a more reactive rhodium hydride ([Rh]-H) catalyst as opposed to the commonly used rhodium chloride ([Rh]-Cl) catalyst. This work unveils opportunities in converting simple arenes into value-added stereogenic silicon compounds.

Highlights

The tremendous success of stereogenic carbon compounds has never ceased to inspire researchers to explore the potentials of stereogenic silicon compounds
The C–H bonds were placed in well-designed positions such that they were predisposed to intercept the Si-[Rh] intermediate, overcoming the low reactivity and poor regioselectivity of the C–H bonds. Since such a pre-organized reaction pattern enjoyed by the intramolecular CH silylation is not available in the intermolecular C–H silylation, the low reactivity of the C–H bonds brings up significant challenges
It is clear that three prerequisites have to be met: (1) a prochiral silane that can be converted into a stereogenic Si in an enantioselective fashion; (2) a substrate design that circumvents the self-reaction of the prochiral silane, and (3) a catalyst system that has high reactivity towards the intermolecular C–H bonds, further alleviating the self-reaction of the prochiral silane

Summary

Introduction

The tremendous success of stereogenic carbon compounds has never ceased to inspire researchers to explore the potentials of stereogenic silicon compounds. We report an example of enantioselective intermolecular C-H silylation (Fig. 1c), which stems from our longterm research in silicon chemistry. Under this new set of conditions with Rh(L3)-H as the catalyst, the reaction showed a better yield (57%) and excellent enantioselectivity (92% ee) (entry 12).

Results

Conclusion