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{{Chembox
{{Chembox
| ImageFile = Rh2Cl2 coe 4.svg
|ImageFile = Rh2Cl2(coe)4corrected.png
| ImageSize =
| ImageAlt =
| IUPACName =
| OtherNames =
|Section1={{Chembox Identifiers
|Section1={{Chembox Identifiers
| CASNo = 12279-09-3
|CASNo = 12279-09-3
| PubChem =
|PubChem = 53384308
|ChemSpiderID = 21613963
| SMILES = }}
|InChI=1S/4C8H14.2ClH.2Rh/c4*1-2-4-6-8-7-5-3-1;;;;/h4*1-2H,3-8H2;2*1H;;/p-2/b4*2-1-;;;;
|InChIKey = ZFCBAJWXKUDJSW-XFCUKONHSA-L
|SMILES = C1CCCC=CCC1.C1CCCC=CCC1.C1CCCC=CCC1.C1CCCC=CCC1.[Cl-].[Cl-].[Rh].[Rh] }}
|Section2={{Chembox Properties
|Section2={{Chembox Properties
| Formula = C<sub>32</sub>H<sub>56</sub>Cl<sub>2</sub>Rh<sub>2</sub>
|Formula = C<sub>32</sub>H<sub>56</sub>Cl<sub>2</sub>Rh<sub>2</sub>
| MolarMass = 717.50
|MolarMass = 717.50
| Appearance = red-brown solid
|Appearance = red-brown solid
}}
| Density =
| MeltingPt =
| BoilingPt =
| Solubility = }}
|Section3={{Chembox Hazards
|Section3={{Chembox Hazards
|GHSPictograms = {{GHS07}}
| MainHazards =
|GHSSignalWord = Warning
| FlashPt =
|HPhrases = {{H-phrases|302|312|315|319|332|335}}
| AutoignitionPt = }}
|PPhrases = {{P-phrases|261|264|270|271|280|301+312|302+352|304+312|304+340|305+351+338|312|321|322|330|332+313|337+313|362|363|403+233|405|501}}
}}
}}
}}


'''Chlorobis(cyclooctene)rhodium dimer''' is an [[organorhodium compound]] with the formula Rh<sub>2</sub>Cl<sub>2</sub>(C<sub>8</sub>H<sub>14</sub>)<sub>4</sub>, where C<sub>8</sub>H<sub>14</sub> is ''cis''-[[cyclooctene]]. Sometimes abbreviated Rh<sub>2</sub>Cl<sub>2</sub>(coe)<sub>4</sub>, it is a red-brown, air-sensitive solid that is a precursor to many other organorhodium compounds and catalysts.
'''Chlorobis(cyclooctene)rhodium dimer''' is an [[organorhodium compound]] with the formula Rh<sub>2</sub>Cl<sub>2</sub>(C<sub>8</sub>H<sub>14</sub>)<sub>4</sub>, where C<sub>8</sub>H<sub>14</sub> is ''cis''-[[cyclooctene]]. Sometimes abbreviated Rh<sub>2</sub>Cl<sub>2</sub>(coe)<sub>4</sub>, it is a red-brown, air-sensitive solid that is a precursor to many other organorhodium compounds and catalysts.


The complex is prepared by treating an alcohol solution of [[water of crystallization|hydrated]] [[rhodium trichloride]] with cyclooctene at room temperature.<ref>Van der Ent, A.; Onderdelinden, A. L. "Chlorobis(cyclooctene)rhodium(I) and di-μ-chlorobis[bis(cryclooctene)iridium] (I) complexes" Inorganic Syntheses 1973, volume 14, pp. 92-5. {{DOI|10.1002/9780470132456.ch18}}</ref> The coe ligands are easily displaced by other more basic [[ligand]]s, more so than the diene ligands in the related complex [[cyclooctadiene rhodium chloride dimer]].
The complex is prepared by treating an alcohol solution of [[water of crystallization|hydrated]] [[rhodium trichloride]] with cyclooctene at room temperature.<ref>Van der Ent, A.; Onderdelinden, A. L. "Chlorobis(cyclooctene)rhodium(I) and di-μ-chlorobis[bis(cryclooctene)iridium] (I) complexes" Inorganic Syntheses 1973, volume 14, pp. 92-5. {{doi|10.1002/9780470132456.ch18}}</ref> The coe ligands are easily displaced by other more basic [[ligand]]s, more so than the diene ligands in the related complex [[cyclooctadiene rhodium chloride dimer]].

==Catalyst for C-H activation==
[[C-H activation]] is often catalyzed by chlorobis(cyclooctene)rhodium dimer as demonstrated in the synthesis of a strained bicyclic enamine.<ref>{{cite journal | last1 = Yotphan | first1 = Sirilata | last2 = Bergman | first2 = Robert G. | last3 = Ellman | first3 = Jonathan A. | title = ''The Stereoselective Formation of Bicyclic Enamines with Bridgehead Unsaturation via Tandem C–H Bond Activation/Alkenylation/ Electrocyclization'' | journal = [[J. Am. Chem. Soc.]] | date = 2008 | volume = 130 | issue = 8| pages = 2452–2453 | doi = 10.1021/ja710981b | pmid = 18247623 | pmc = 3062933 }}</ref>
:[[Image:BergMannCHActivation2008.svg|400px|center|C–H bond activation Yotphan 2008]]
The synthesis of a mescaline analogue involves enantioselective annulation of an aryl imine via a C-H activation.<ref>{{Cite journal|title = Synthesis of a Tricyclic Mescaline Analogue by Catalytic C−H Bond Activation|journal = Organic Letters|date = 2003-04-01|issn = 1523-7060|pages = 1301–1303|volume = 5|issue = 8|doi = 10.1021/ol034228d|first1 = Kateri A.|last1 = Ahrendt|first2 = Robert G.|last2 = Bergman|first3 = Jonathan A.|last3 = Ellman|pmid=12688744}}</ref>
[[File:Mescalineprep.jpg|centre|frameless|482x482px]]
The total synthesis of lithospermic acid employs "guided C-H functionalization" late stage to a highly functionalized system. The directing group, a [[Chirality (chemistry)|chiral]] nonracemic imine, is capable of performing an intramolecular alkylation, which allows for the rhodium-catalyzed conversion of imine to the dihydrobenzofuran.<ref>{{cite journal | title = Total Synthesis of (+)-Lithospermic Acid by Asymmetric Intramolecular Alkylation via Catalytic C-H Bond Activation | journal = J. Am. Chem. Soc. | year = 2005 | volume = 127 | issue = 39 | pages = 13496–13497 | last1 = O'Malley | first1 = S. J. | last2 = Tan | first2 = K. L. | last3 = Watzke | first3 = A. | last4 = Bergman | first4 = R. G. | last5 = Ellman | first5 = J. A. | doi = 10.1021/ja052680h | pmid=16190703}}</ref>


[[File:Natural Product Synth Ellman Figure 1.png|750px|center|Key step in synthesis of lithospermic acid]]
==References==
==References==
<references />
<references />
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{{Rhodium compounds}}
{{Rhodium compounds}}


[[Category:Rhodium compounds]]
[[Category:Organorhodium compounds]]
[[Category:Homogeneous catalysis]]
[[Category:Homogeneous catalysis]]
[[Category:Alkene complexes]]
[[Category:Alkene complexes]]
[[Category:Dimers (chemistry)]]
[[Category:Dimers (chemistry)]]
[[Category:Chloro complexes]]
[[Category:Rhodium(I) compounds]]

Latest revision as of 17:17, 18 June 2024

Chlorobis(cyclooctene)rhodium dimer
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.152.028 Edit this at Wikidata
  • InChI=1S/4C8H14.2ClH.2Rh/c4*1-2-4-6-8-7-5-3-1;;;;/h4*1-2H,3-8H2;2*1H;;/p-2/b4*2-1-;;;;
    Key: ZFCBAJWXKUDJSW-XFCUKONHSA-L
  • C1CCCC=CCC1.C1CCCC=CCC1.C1CCCC=CCC1.C1CCCC=CCC1.[Cl-].[Cl-].[Rh].[Rh]
Properties
C32H56Cl2Rh2
Molar mass 717.50
Appearance red-brown solid
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H302, H312, H315, H319, H332, H335
P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P312, P321, P322, P330, P332+P313, P337+P313, P362, P363, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Chlorobis(cyclooctene)rhodium dimer is an organorhodium compound with the formula Rh2Cl2(C8H14)4, where C8H14 is cis-cyclooctene. Sometimes abbreviated Rh2Cl2(coe)4, it is a red-brown, air-sensitive solid that is a precursor to many other organorhodium compounds and catalysts.

The complex is prepared by treating an alcohol solution of hydrated rhodium trichloride with cyclooctene at room temperature.[1] The coe ligands are easily displaced by other more basic ligands, more so than the diene ligands in the related complex cyclooctadiene rhodium chloride dimer.

Catalyst for C-H activation

[edit]

C-H activation is often catalyzed by chlorobis(cyclooctene)rhodium dimer as demonstrated in the synthesis of a strained bicyclic enamine.[2]

C–H bond activation Yotphan 2008
C–H bond activation Yotphan 2008

The synthesis of a mescaline analogue involves enantioselective annulation of an aryl imine via a C-H activation.[3]

The total synthesis of lithospermic acid employs "guided C-H functionalization" late stage to a highly functionalized system. The directing group, a chiral nonracemic imine, is capable of performing an intramolecular alkylation, which allows for the rhodium-catalyzed conversion of imine to the dihydrobenzofuran.[4]

Key step in synthesis of lithospermic acid
Key step in synthesis of lithospermic acid

References

[edit]
  1. ^ Van der Ent, A.; Onderdelinden, A. L. "Chlorobis(cyclooctene)rhodium(I) and di-μ-chlorobis[bis(cryclooctene)iridium] (I) complexes" Inorganic Syntheses 1973, volume 14, pp. 92-5. doi:10.1002/9780470132456.ch18
  2. ^ Yotphan, Sirilata; Bergman, Robert G.; Ellman, Jonathan A. (2008). "The Stereoselective Formation of Bicyclic Enamines with Bridgehead Unsaturation via Tandem C–H Bond Activation/Alkenylation/ Electrocyclization". J. Am. Chem. Soc. 130 (8): 2452–2453. doi:10.1021/ja710981b. PMC 3062933. PMID 18247623.
  3. ^ Ahrendt, Kateri A.; Bergman, Robert G.; Ellman, Jonathan A. (2003-04-01). "Synthesis of a Tricyclic Mescaline Analogue by Catalytic C−H Bond Activation". Organic Letters. 5 (8): 1301–1303. doi:10.1021/ol034228d. ISSN 1523-7060. PMID 12688744.
  4. ^ O'Malley, S. J.; Tan, K. L.; Watzke, A.; Bergman, R. G.; Ellman, J. A. (2005). "Total Synthesis of (+)-Lithospermic Acid by Asymmetric Intramolecular Alkylation via Catalytic C-H Bond Activation". J. Am. Chem. Soc. 127 (39): 13496–13497. doi:10.1021/ja052680h. PMID 16190703.
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