Kinetic resolution and parallel kinetic resolution of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives.
Conjugate addition of lithium dibenzylamide to methyl 5-isopropyl, 5-phenyl- and 5-tert-butyl-cyclopentene-1-carboxylates occurs with high levels of substrate control (>88% de), with preferential addition to the face of the cyclic alpha,beta-unsaturated acceptor anti- to the stereodirecting 5...
| Main Authors: | , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2005
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| _version_ | 1826300033974140928 |
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| author | Davies, S Garner, A Long, M Morrison, R Roberts, P Savory, E Smith, A Sweet, M Withey, J |
| author_facet | Davies, S Garner, A Long, M Morrison, R Roberts, P Savory, E Smith, A Sweet, M Withey, J |
| author_sort | Davies, S |
| collection | OXFORD |
| description | Conjugate addition of lithium dibenzylamide to methyl 5-isopropyl, 5-phenyl- and 5-tert-butyl-cyclopentene-1-carboxylates occurs with high levels of substrate control (>88% de), with preferential addition to the face of the cyclic alpha,beta-unsaturated acceptor anti- to the stereodirecting 5-alkyl substituent. Treatment of a range of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates with both lithium (+/-)-N-benzyl-N-alpha-methylbenzylamide and lithium (+/-)-N-3,4-dimethoxybenzyl-N-alpha-methylbenzylamide indicates significant enantiorecognition in their mutual kinetic resolutions, with preferential addition anti- to the 5-alkyl substituent, giving the 1,2-syn-1,5-anti-arrangement (E >16) after enolate protonation anti- to the amino functionality. The kinetic resolution of a range of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates with lithium (S)-N-benzyl-N-alpha-methylbenzylamide, and their efficient parallel kinetic resolution with a pseudoenantiomeric mixture of lithium (S)-N-benzyl-N-alpha-methylbenzylamide and lithium (R)-N-3,4-dimethoxybenzyl-N-alpha-methylbenzylamide are also demonstrated, giving a range of 5-alkyl-cispentacin derivatives in >98% de and high ee after N-deprotection. |
| first_indexed | 2024-03-07T05:11:00Z |
| format | Journal article |
| id | oxford-uuid:db8a880f-253f-4920-a646-3b0e359722ed |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T05:11:00Z |
| publishDate | 2005 |
| record_format | dspace |
| spelling | oxford-uuid:db8a880f-253f-4920-a646-3b0e359722ed2022-03-27T09:11:25ZKinetic resolution and parallel kinetic resolution of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:db8a880f-253f-4920-a646-3b0e359722edEnglishSymplectic Elements at Oxford2005Davies, SGarner, ALong, MMorrison, RRoberts, PSavory, ESmith, ASweet, MWithey, JConjugate addition of lithium dibenzylamide to methyl 5-isopropyl, 5-phenyl- and 5-tert-butyl-cyclopentene-1-carboxylates occurs with high levels of substrate control (>88% de), with preferential addition to the face of the cyclic alpha,beta-unsaturated acceptor anti- to the stereodirecting 5-alkyl substituent. Treatment of a range of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates with both lithium (+/-)-N-benzyl-N-alpha-methylbenzylamide and lithium (+/-)-N-3,4-dimethoxybenzyl-N-alpha-methylbenzylamide indicates significant enantiorecognition in their mutual kinetic resolutions, with preferential addition anti- to the 5-alkyl substituent, giving the 1,2-syn-1,5-anti-arrangement (E >16) after enolate protonation anti- to the amino functionality. The kinetic resolution of a range of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates with lithium (S)-N-benzyl-N-alpha-methylbenzylamide, and their efficient parallel kinetic resolution with a pseudoenantiomeric mixture of lithium (S)-N-benzyl-N-alpha-methylbenzylamide and lithium (R)-N-3,4-dimethoxybenzyl-N-alpha-methylbenzylamide are also demonstrated, giving a range of 5-alkyl-cispentacin derivatives in >98% de and high ee after N-deprotection. |
| spellingShingle | Davies, S Garner, A Long, M Morrison, R Roberts, P Savory, E Smith, A Sweet, M Withey, J Kinetic resolution and parallel kinetic resolution of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives. |
| title | Kinetic resolution and parallel kinetic resolution of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives. |
| title_full | Kinetic resolution and parallel kinetic resolution of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives. |
| title_fullStr | Kinetic resolution and parallel kinetic resolution of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives. |
| title_full_unstemmed | Kinetic resolution and parallel kinetic resolution of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives. |
| title_short | Kinetic resolution and parallel kinetic resolution of methyl (+/-)-5-alkyl-cyclopentene-1-carboxylates for the asymmetric synthesis of 5-alkyl-cispentacin derivatives. |
| title_sort | kinetic resolution and parallel kinetic resolution of methyl 5 alkyl cyclopentene 1 carboxylates for the asymmetric synthesis of 5 alkyl cispentacin derivatives |
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