Mechanistic insights into stereoselective catalysis-the effects of counterions in a CuII-bissulfoximine-catalyzed Diels-Alder reaction.
The initial steps of an enantioselective Diels-Alder reaction catalyzed by a CuII-bissulfoximine complex were followed by EXAFS (EXAFS=extended X-ray absorption fine structure), EPR (EPR=electron paramagnetic resonance) spectroscopy (CW-EPR, FID-detected EPR, pulse ENDOR, HYSCORE; CW=continuous wave...
| Main Authors: | , , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
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2007
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| _version_ | 1826307175683719168 |
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| author | Bolm, C Martin, M Gescheidt, G Palivan, C Stanoeva, T Bertagnolli, H Feth, M Schweiger, A Mitrikas, G Harmer, J |
| author_facet | Bolm, C Martin, M Gescheidt, G Palivan, C Stanoeva, T Bertagnolli, H Feth, M Schweiger, A Mitrikas, G Harmer, J |
| author_sort | Bolm, C |
| collection | OXFORD |
| description | The initial steps of an enantioselective Diels-Alder reaction catalyzed by a CuII-bissulfoximine complex were followed by EXAFS (EXAFS=extended X-ray absorption fine structure), EPR (EPR=electron paramagnetic resonance) spectroscopy (CW-EPR, FID-detected EPR, pulse ENDOR, HYSCORE; CW=continuous wave; ENDOR=electron nuclear double resonance; HYSCORE=hyperfine sublevel correlation; FID=free induction decay), and UV-visible spectroscopy. The complexes formed between the parent CuX2 (X=Cl-, Br-, TfO-, SbF6-) salts, the chiral bissulfoximine ligand (S,S)-1, and N-(1-oxoprop-2-en-1-yl)oxazolidin-2-one (2) as the substrate in CH2Cl2 were investigated in frozen and fluid solution. In all cases, penta- or hexacoordinated CuII centers were established. The complexes with counterions indicating high stereoselectivity (TfO- and SbF6-) reveal one unique species in which substrate 2 binds to pseudoequatorial positions (via O atoms), shifting the counterions to axial locations. On the other hand, those lacking stereoselectivity (X=Cl- and Br-) form two species in which the parent halogen anions remain at equatorial positions preventing the formation of geometries compatible with those found for X=TfO- and SbF6-. |
| first_indexed | 2024-03-07T06:58:59Z |
| format | Journal article |
| id | oxford-uuid:ff1850b1-1191-4b08-a8c9-e9fba011a61f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:58:59Z |
| publishDate | 2007 |
| record_format | dspace |
| spelling | oxford-uuid:ff1850b1-1191-4b08-a8c9-e9fba011a61f2022-03-27T13:41:56ZMechanistic insights into stereoselective catalysis-the effects of counterions in a CuII-bissulfoximine-catalyzed Diels-Alder reaction.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:ff1850b1-1191-4b08-a8c9-e9fba011a61fEnglishSymplectic Elements at Oxford2007Bolm, CMartin, MGescheidt, GPalivan, CStanoeva, TBertagnolli, HFeth, MSchweiger, AMitrikas, GHarmer, JThe initial steps of an enantioselective Diels-Alder reaction catalyzed by a CuII-bissulfoximine complex were followed by EXAFS (EXAFS=extended X-ray absorption fine structure), EPR (EPR=electron paramagnetic resonance) spectroscopy (CW-EPR, FID-detected EPR, pulse ENDOR, HYSCORE; CW=continuous wave; ENDOR=electron nuclear double resonance; HYSCORE=hyperfine sublevel correlation; FID=free induction decay), and UV-visible spectroscopy. The complexes formed between the parent CuX2 (X=Cl-, Br-, TfO-, SbF6-) salts, the chiral bissulfoximine ligand (S,S)-1, and N-(1-oxoprop-2-en-1-yl)oxazolidin-2-one (2) as the substrate in CH2Cl2 were investigated in frozen and fluid solution. In all cases, penta- or hexacoordinated CuII centers were established. The complexes with counterions indicating high stereoselectivity (TfO- and SbF6-) reveal one unique species in which substrate 2 binds to pseudoequatorial positions (via O atoms), shifting the counterions to axial locations. On the other hand, those lacking stereoselectivity (X=Cl- and Br-) form two species in which the parent halogen anions remain at equatorial positions preventing the formation of geometries compatible with those found for X=TfO- and SbF6-. |
| spellingShingle | Bolm, C Martin, M Gescheidt, G Palivan, C Stanoeva, T Bertagnolli, H Feth, M Schweiger, A Mitrikas, G Harmer, J Mechanistic insights into stereoselective catalysis-the effects of counterions in a CuII-bissulfoximine-catalyzed Diels-Alder reaction. |
| title | Mechanistic insights into stereoselective catalysis-the effects of counterions in a CuII-bissulfoximine-catalyzed Diels-Alder reaction. |
| title_full | Mechanistic insights into stereoselective catalysis-the effects of counterions in a CuII-bissulfoximine-catalyzed Diels-Alder reaction. |
| title_fullStr | Mechanistic insights into stereoselective catalysis-the effects of counterions in a CuII-bissulfoximine-catalyzed Diels-Alder reaction. |
| title_full_unstemmed | Mechanistic insights into stereoselective catalysis-the effects of counterions in a CuII-bissulfoximine-catalyzed Diels-Alder reaction. |
| title_short | Mechanistic insights into stereoselective catalysis-the effects of counterions in a CuII-bissulfoximine-catalyzed Diels-Alder reaction. |
| title_sort | mechanistic insights into stereoselective catalysis the effects of counterions in a cuii bissulfoximine catalyzed diels alder reaction |
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