The structures and reactivity of NHC-supported copper(i) triphenylgermyls

Rex S.C. Charman; Nick J. Evans; Laura E. English; Samuel E. Neale; Petra Vasko; Mary F. Mahon; David J. Liptrot

doi:10.1039/D3SC05862J

The structures and reactivity of NHC-supported copper(i) triphenylgermyls

Rex S.C. Charman, Nick J. Evans, Laura E. English, Samuel E. Neale, Petra Vasko, Mary F. Mahon, David J. Liptrot

Research output: Contribution to journal › Article › peer-review

1 Citation (SciVal)

Abstract

Deprotonation of triphenyl germane with NHC-supported copper alkoxides afforded four novel (NHC)CuGePh₃ complexes. Of these, (IPr)CuGePh₃ (IPr = :C{N(2,6-iPr₂C₆H₃)CH}₂) was selected for further investigation. Analysis by EDA-NOCV indicates it to be a germyl nucleophile and its σ-bond metathesis reaction with a range of p-block halides confirmed it to be a convenient source of [Ph₃Ge]⁻. The Cu-Ge bond of (IPr)CuGePh₃ underwent π-bond insertions with tBuNCS, CS₂, and PhNCO to furnish a series of germyl substituted carboxylate derivatives, (IPr)CuXC(Y)GePh₃ (X = S, NPh; Y = S, NtBu, O), which were structurally characterised. (IPr)CuGePh₃ inserted phenyl acetylene, providing both the Markovnikov and anti-Markovnikov products. The (NHC)CuGePh₃ compounds were validated as catalytic intermediates; addition of 10 mol% of NHC-copper(i) alkoxide to a mixture of triphenyl germane and a tin(iv) alkoxide resulted in a tin/germanium cross coupling with concomitant formation of alcohol. Moreover, a catalytic hydrogermylation of Michael acceptors was developed with Ph₃GeH adding to 7 activated alkenes in good conversions and yields in the presence of 10 mol% of NHC-copper(i) alkoxide. In all cases, this reaction provided the β-germylated substrate implicating nucleophilicity at germanium.

Original language	English
Number of pages	10
Journal	Chemical Science
DOIs	https://doi.org/10.1039/D3SC05862J https://doi.org/10.1039/d3sc05862j
Publication status	Published - 1 Dec 2023

Bibliographical note

Publisher Copyright:
© 2024 The Royal Society of Chemistry.

Funding

DJL thanks the Royal Society for the support of a University Research Fellowship. LEE thanks the EPSRC for funding (EP/L016354/1) for a PhD studentship. PV would like to thank the Academy of Finland (grant numbers 346565 and 338271) and Jenny and Antti Wihuri Foundation for funding and the CSC – IT Center for Science, Finland, for computational resources.

Funders	Funder number
Engineering and Physical Sciences Research Council	EP/L016354/1
Royal Society
Commonwealth Scholarship Commission
Academy of Finland	346565, 338271
Jenny ja Antti Wihurin Rahasto

ASJC Scopus subject areas

General Chemistry

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10.1039/d3sc05862j

http://xlink.rsc.org/?DOI=D3SC05862J

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title = "The structures and reactivity of NHC-supported copper(i) triphenylgermyls",

abstract = "Deprotonation of triphenyl germane with NHC-supported copper alkoxides afforded four novel (NHC)CuGePh3 complexes. Of these, (IPr)CuGePh3 (IPr = :C{N(2,6-iPr2C6H3)CH}2) was selected for further investigation. Analysis by EDA-NOCV indicates it to be a germyl nucleophile and its σ-bond metathesis reaction with a range of p-block halides confirmed it to be a convenient source of [Ph3Ge]−. The Cu-Ge bond of (IPr)CuGePh3 underwent π-bond insertions with tBuNCS, CS2, and PhNCO to furnish a series of germyl substituted carboxylate derivatives, (IPr)CuXC(Y)GePh3 (X = S, NPh; Y = S, NtBu, O), which were structurally characterised. (IPr)CuGePh3 inserted phenyl acetylene, providing both the Markovnikov and anti-Markovnikov products. The (NHC)CuGePh3 compounds were validated as catalytic intermediates; addition of 10 mol% of NHC-copper(i) alkoxide to a mixture of triphenyl germane and a tin(iv) alkoxide resulted in a tin/germanium cross coupling with concomitant formation of alcohol. Moreover, a catalytic hydrogermylation of Michael acceptors was developed with Ph3GeH adding to 7 activated alkenes in good conversions and yields in the presence of 10 mol% of NHC-copper(i) alkoxide. In all cases, this reaction provided the β-germylated substrate implicating nucleophilicity at germanium.",

author = "Charman, {Rex S.C.} and Evans, {Nick J.} and English, {Laura E.} and Neale, {Samuel E.} and Petra Vasko and Mahon, {Mary F.} and Liptrot, {David J.}",

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AU - Charman, Rex S.C.

AU - Evans, Nick J.

AU - English, Laura E.

AU - Neale, Samuel E.

AU - Vasko, Petra

AU - Mahon, Mary F.

AU - Liptrot, David J.

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N2 - Deprotonation of triphenyl germane with NHC-supported copper alkoxides afforded four novel (NHC)CuGePh3 complexes. Of these, (IPr)CuGePh3 (IPr = :C{N(2,6-iPr2C6H3)CH}2) was selected for further investigation. Analysis by EDA-NOCV indicates it to be a germyl nucleophile and its σ-bond metathesis reaction with a range of p-block halides confirmed it to be a convenient source of [Ph3Ge]−. The Cu-Ge bond of (IPr)CuGePh3 underwent π-bond insertions with tBuNCS, CS2, and PhNCO to furnish a series of germyl substituted carboxylate derivatives, (IPr)CuXC(Y)GePh3 (X = S, NPh; Y = S, NtBu, O), which were structurally characterised. (IPr)CuGePh3 inserted phenyl acetylene, providing both the Markovnikov and anti-Markovnikov products. The (NHC)CuGePh3 compounds were validated as catalytic intermediates; addition of 10 mol% of NHC-copper(i) alkoxide to a mixture of triphenyl germane and a tin(iv) alkoxide resulted in a tin/germanium cross coupling with concomitant formation of alcohol. Moreover, a catalytic hydrogermylation of Michael acceptors was developed with Ph3GeH adding to 7 activated alkenes in good conversions and yields in the presence of 10 mol% of NHC-copper(i) alkoxide. In all cases, this reaction provided the β-germylated substrate implicating nucleophilicity at germanium.

AB - Deprotonation of triphenyl germane with NHC-supported copper alkoxides afforded four novel (NHC)CuGePh3 complexes. Of these, (IPr)CuGePh3 (IPr = :C{N(2,6-iPr2C6H3)CH}2) was selected for further investigation. Analysis by EDA-NOCV indicates it to be a germyl nucleophile and its σ-bond metathesis reaction with a range of p-block halides confirmed it to be a convenient source of [Ph3Ge]−. The Cu-Ge bond of (IPr)CuGePh3 underwent π-bond insertions with tBuNCS, CS2, and PhNCO to furnish a series of germyl substituted carboxylate derivatives, (IPr)CuXC(Y)GePh3 (X = S, NPh; Y = S, NtBu, O), which were structurally characterised. (IPr)CuGePh3 inserted phenyl acetylene, providing both the Markovnikov and anti-Markovnikov products. The (NHC)CuGePh3 compounds were validated as catalytic intermediates; addition of 10 mol% of NHC-copper(i) alkoxide to a mixture of triphenyl germane and a tin(iv) alkoxide resulted in a tin/germanium cross coupling with concomitant formation of alcohol. Moreover, a catalytic hydrogermylation of Michael acceptors was developed with Ph3GeH adding to 7 activated alkenes in good conversions and yields in the presence of 10 mol% of NHC-copper(i) alkoxide. In all cases, this reaction provided the β-germylated substrate implicating nucleophilicity at germanium.

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The structures and reactivity of NHC-supported copper(i) triphenylgermyls

Abstract

Bibliographical note

Funding

ASJC Scopus subject areas

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