Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators
Ring-opening metathesis polymerization (ROMP) of methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate (PhEtNNBE; (S) and racemic) was investigated employing six molybdenum and tungsten imido alkylidene initiators and two tungsten oxo alkylidene initiators. Of the six initiators that...
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| Format: | Article |
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American Chemical Society (ACS)
2017
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| Online Access: | http://hdl.handle.net/1721.1/108581 https://orcid.org/0000-0002-1788-4100 https://orcid.org/0000-0001-5827-3552 |
| _version_ | 1811094213091131392 |
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| author | Jeong, Hyangsoo Ng, Victor Wee Lin Borner, Janna Schrock, Richard Royce |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Jeong, Hyangsoo Ng, Victor Wee Lin Borner, Janna Schrock, Richard Royce |
| author_sort | Jeong, Hyangsoo |
| collection | MIT |
| description | Ring-opening metathesis polymerization (ROMP) of methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate (PhEtNNBE; (S) and racemic) was investigated employing six molybdenum and tungsten imido alkylidene initiators and two tungsten oxo alkylidene initiators. Of the six initiators that we proposed should yield cis,syndiotactic-poly[(S)-PhEtNNBE], two molybdenum OHMT alkylidene initiators, Mo(NR)(CHMe2Ph)(pyr)(OHMT) (R = 1-adamantyl (Ad) or 2,6-Me[subscript 2]C[subscript 6]H[subscript 3] (Ar′); OHMT = O-2,6-mesityl[subscript 2]C[subscript 6]H[subscript 3]; pyr = pyrrolide), and two tungsten oxo alkylidene initiators, W(O)(CHMe[subscript 2]Ph)(2,5-dimethylpyrrolide)(PMe2Ph)(OR) (OR = OHMT or (R)-OBr[subscript 2]Bitet where (R)-Br[subscript 2]BitetOH = (R)-3,3′-dibromo-2′-(tert-butyldimethylsilyloxy)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl-2-ol), produced essentially pure cis,syndiotactic-poly[(S)-PhEtNNBE]. Essentially pure cis,isotactic-poly[(S)-PhEtNNBE] was formed when (S)-PhEtNNBE was polymerized by Mo(NAr′)(CHCMe2Ph)(OBiphen[subscript CF3])(thf) or W(NAr′)(CHCMe[subscript 2]Ph)((S)-OBiphenMe) (OBiphenCF3 = 3,3′-di-tert-butyl-5,5′-bistrifluoromethyl-6,6′-dimethyl-1,1′-biphenyl-2,2′-diolate; (S)-OBiphen[subscript Me] = 3,3′-di-tert-butyl-5,5′,6,6′-tetramethyl-1,1′-biphenyl-2,2′-diolate). The best initiator for ROMP of rac-PhEtNNBE was Mo(NAd)(CHMe[subscript 2]Ph)(pyr)(OHMT) at 0 °C, which led to a polymer that is biased (∼80%) toward a cis,syndiotactic structure and that contains alternating enantiomers in the chain (cis,syndio,alt-poly[(rac)-PhEtNNBE]). |
| first_indexed | 2024-09-23T15:56:38Z |
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| id | mit-1721.1/108581 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:56:38Z |
| publishDate | 2017 |
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| spelling | mit-1721.1/1085812022-10-02T05:14:58Z Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators Jeong, Hyangsoo Ng, Victor Wee Lin Borner, Janna Schrock, Richard Royce Massachusetts Institute of Technology. Department of Chemistry Schrock, Richard Royce Jeong, Hyangsoo Ng, Victor Wee Lin Borner, Janna Schrock, Richard Royce Ring-opening metathesis polymerization (ROMP) of methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate (PhEtNNBE; (S) and racemic) was investigated employing six molybdenum and tungsten imido alkylidene initiators and two tungsten oxo alkylidene initiators. Of the six initiators that we proposed should yield cis,syndiotactic-poly[(S)-PhEtNNBE], two molybdenum OHMT alkylidene initiators, Mo(NR)(CHMe2Ph)(pyr)(OHMT) (R = 1-adamantyl (Ad) or 2,6-Me[subscript 2]C[subscript 6]H[subscript 3] (Ar′); OHMT = O-2,6-mesityl[subscript 2]C[subscript 6]H[subscript 3]; pyr = pyrrolide), and two tungsten oxo alkylidene initiators, W(O)(CHMe[subscript 2]Ph)(2,5-dimethylpyrrolide)(PMe2Ph)(OR) (OR = OHMT or (R)-OBr[subscript 2]Bitet where (R)-Br[subscript 2]BitetOH = (R)-3,3′-dibromo-2′-(tert-butyldimethylsilyloxy)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl-2-ol), produced essentially pure cis,syndiotactic-poly[(S)-PhEtNNBE]. Essentially pure cis,isotactic-poly[(S)-PhEtNNBE] was formed when (S)-PhEtNNBE was polymerized by Mo(NAr′)(CHCMe2Ph)(OBiphen[subscript CF3])(thf) or W(NAr′)(CHCMe[subscript 2]Ph)((S)-OBiphenMe) (OBiphenCF3 = 3,3′-di-tert-butyl-5,5′-bistrifluoromethyl-6,6′-dimethyl-1,1′-biphenyl-2,2′-diolate; (S)-OBiphen[subscript Me] = 3,3′-di-tert-butyl-5,5′,6,6′-tetramethyl-1,1′-biphenyl-2,2′-diolate). The best initiator for ROMP of rac-PhEtNNBE was Mo(NAd)(CHMe[subscript 2]Ph)(pyr)(OHMT) at 0 °C, which led to a polymer that is biased (∼80%) toward a cis,syndiotactic structure and that contains alternating enantiomers in the chain (cis,syndio,alt-poly[(rac)-PhEtNNBE]). United States. Department of Energy (grant DE-FG0286ER13564) Singapore. Agency for Science, Technology and Research (A*STAR International Fellowship) Alexander von Humboldt-Stiftung (Feodor Lynen Research Fellowship) 2017-05-02T15:38:54Z 2017-05-02T15:38:54Z 2015-03 Article http://purl.org/eprint/type/JournalArticle 0024-9297 1520-5835 http://hdl.handle.net/1721.1/108581 Jeong, Hyangsoo, Victor W. L. Ng, Janna Börner, and Richard R. Schrock. “ Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-Phenylethyl)-2-Azabicyclo[2.2.1]hept-5-Ene-3-Carboxylate by Molybdenum and Tungsten Initiators .” Macromolecules 48, no. 7 (April 14, 2015): 2006–2012. https://orcid.org/0000-0002-1788-4100 https://orcid.org/0000-0001-5827-3552 en_US http://pubs.acs.org/doi/abs/10.1021/acs.macromol.5b00264 Macromolecules Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Chemical Society (ACS) Prof. Schrock |
| spellingShingle | Jeong, Hyangsoo Ng, Victor Wee Lin Borner, Janna Schrock, Richard Royce Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators |
| title | Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators |
| title_full | Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators |
| title_fullStr | Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators |
| title_full_unstemmed | Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators |
| title_short | Stereoselective Ring-Opening Metathesis Polymerization (ROMP) of Methyl-N-(1-phenylethyl)-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate by Molybdenum and Tungsten Initiators |
| title_sort | stereoselective ring opening metathesis polymerization romp of methyl n 1 phenylethyl 2 azabicyclo 2 2 1 hept 5 ene 3 carboxylate by molybdenum and tungsten initiators |
| url | http://hdl.handle.net/1721.1/108581 https://orcid.org/0000-0002-1788-4100 https://orcid.org/0000-0001-5827-3552 |
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