THE ASYMMETRIC-SYNTHESIS OF BETA-LACTAMS - STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND SUBSEQUENT ALKYLATIONS OF E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH=CHME] - X-RAY CRYSTAL-STRUCTURE OF (RS)-E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH - CHME]

Michael addition of methyllithium to the E-crotonyl complex (RS)-[η5-C5H5)Fe(CO)-(PPh3 )COCHCHMe] followed by trapping of the resultant enolate with methyl iodide gives (RS)-[(η5-C5H5)Fe(CO)(PPh3 )COCH(Me)CHMe2] (d.e. > 100:1), also generated by treatment of (RS)-[(η5-C5H5)Fe(CO)(PPh3 )COCH2C...

全面介紹

書目詳細資料
Main Authors: Davies, S, Dordorhedgecock, I, Sutton, K, Walker, J, Jones, R, Prout, K
格式: Journal article
語言:English
出版: 1986
_version_ 1826302450205720576
author Davies, S
Dordorhedgecock, I
Sutton, K
Walker, J
Jones, R
Prout, K
author_facet Davies, S
Dordorhedgecock, I
Sutton, K
Walker, J
Jones, R
Prout, K
author_sort Davies, S
collection OXFORD
description Michael addition of methyllithium to the E-crotonyl complex (RS)-[η5-C5H5)Fe(CO)-(PPh3 )COCHCHMe] followed by trapping of the resultant enolate with methyl iodide gives (RS)-[(η5-C5H5)Fe(CO)(PPh3 )COCH(Me)CHMe2] (d.e. > 100:1), also generated by treatment of (RS)-[(η5-C5H5)Fe(CO)(PPh3 )COCH2CH(OMe)2] with three equivalents of methyllithium and methyl iodide. Addition of n-butyllithium to the (RS)-E-crotonyl complex followed by protonation with methanol occurs with high diastereoselectivity. Quenching with methyl iodide gives (RS)-[(η5-C5H5)Fe(CO)(PPh3 )COCH(Me)CH(Me)n-Bu], also generated by treating either diastereoisomer of [(η5C5H5)Fe(CO)(PPh3)COC H2CH(Me)OMe] with two equivalents of n-butyllithium and methyl iodide. Decomplexatlon gives the known erythro-2,3-dimethyl-heptanoic acid. Similarly, Michael addition of lithium benzylamide and electrophilic quenching with methanol or methyl iodide occurs with high diastereoselectivity and gives upon decomplexation, 4-methyl- and cis-3,4-dimethyl-N-benzyl-β-lactams respectively. The stereochemical results are rationalised by addition occurring to the E-crotonyl complex in the anti (CO to CO) and cisoid conformation and subsequent alkylation of the unhindered face of the E-enolate generated. Confirmation is provided by an X-ray crystal structure analysis of (RS)-E-[(η5-C5H5)Fe(CO)(PPh3 )COCHCHMe]. When repeated with the optically pure (S)-E-crotonyl complex, decomplexation gives essentially optically pure (2R),(3R)-(-)-N-benzyl-2,3-dimethylheptanamide, (4S)-(-)-4-methyl- and (3R),(4S)-(-)-cis-3,4-dimethyl-N-benzyl-β-lactams. © 1986.
first_indexed 2024-03-07T05:47:43Z
format Journal article
id oxford-uuid:e7c611a0-b94e-4c79-8560-b0ef6a470a0e
institution University of Oxford
language English
last_indexed 2024-03-07T05:47:43Z
publishDate 1986
record_format dspace
spelling oxford-uuid:e7c611a0-b94e-4c79-8560-b0ef6a470a0e2022-03-27T10:41:32ZTHE ASYMMETRIC-SYNTHESIS OF BETA-LACTAMS - STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND SUBSEQUENT ALKYLATIONS OF E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH=CHME] - X-RAY CRYSTAL-STRUCTURE OF (RS)-E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH - CHME]Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:e7c611a0-b94e-4c79-8560-b0ef6a470a0eEnglishSymplectic Elements at Oxford1986Davies, SDordorhedgecock, ISutton, KWalker, JJones, RProut, KMichael addition of methyllithium to the E-crotonyl complex (RS)-[η5-C5H5)Fe(CO)-(PPh3 )COCHCHMe] followed by trapping of the resultant enolate with methyl iodide gives (RS)-[(η5-C5H5)Fe(CO)(PPh3 )COCH(Me)CHMe2] (d.e. > 100:1), also generated by treatment of (RS)-[(η5-C5H5)Fe(CO)(PPh3 )COCH2CH(OMe)2] with three equivalents of methyllithium and methyl iodide. Addition of n-butyllithium to the (RS)-E-crotonyl complex followed by protonation with methanol occurs with high diastereoselectivity. Quenching with methyl iodide gives (RS)-[(η5-C5H5)Fe(CO)(PPh3 )COCH(Me)CH(Me)n-Bu], also generated by treating either diastereoisomer of [(η5C5H5)Fe(CO)(PPh3)COC H2CH(Me)OMe] with two equivalents of n-butyllithium and methyl iodide. Decomplexatlon gives the known erythro-2,3-dimethyl-heptanoic acid. Similarly, Michael addition of lithium benzylamide and electrophilic quenching with methanol or methyl iodide occurs with high diastereoselectivity and gives upon decomplexation, 4-methyl- and cis-3,4-dimethyl-N-benzyl-β-lactams respectively. The stereochemical results are rationalised by addition occurring to the E-crotonyl complex in the anti (CO to CO) and cisoid conformation and subsequent alkylation of the unhindered face of the E-enolate generated. Confirmation is provided by an X-ray crystal structure analysis of (RS)-E-[(η5-C5H5)Fe(CO)(PPh3 )COCHCHMe]. When repeated with the optically pure (S)-E-crotonyl complex, decomplexation gives essentially optically pure (2R),(3R)-(-)-N-benzyl-2,3-dimethylheptanamide, (4S)-(-)-4-methyl- and (3R),(4S)-(-)-cis-3,4-dimethyl-N-benzyl-β-lactams. © 1986.
spellingShingle Davies, S
Dordorhedgecock, I
Sutton, K
Walker, J
Jones, R
Prout, K
THE ASYMMETRIC-SYNTHESIS OF BETA-LACTAMS - STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND SUBSEQUENT ALKYLATIONS OF E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH=CHME] - X-RAY CRYSTAL-STRUCTURE OF (RS)-E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH - CHME]
title THE ASYMMETRIC-SYNTHESIS OF BETA-LACTAMS - STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND SUBSEQUENT ALKYLATIONS OF E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH=CHME] - X-RAY CRYSTAL-STRUCTURE OF (RS)-E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH - CHME]
title_full THE ASYMMETRIC-SYNTHESIS OF BETA-LACTAMS - STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND SUBSEQUENT ALKYLATIONS OF E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH=CHME] - X-RAY CRYSTAL-STRUCTURE OF (RS)-E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH - CHME]
title_fullStr THE ASYMMETRIC-SYNTHESIS OF BETA-LACTAMS - STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND SUBSEQUENT ALKYLATIONS OF E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH=CHME] - X-RAY CRYSTAL-STRUCTURE OF (RS)-E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH - CHME]
title_full_unstemmed THE ASYMMETRIC-SYNTHESIS OF BETA-LACTAMS - STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND SUBSEQUENT ALKYLATIONS OF E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH=CHME] - X-RAY CRYSTAL-STRUCTURE OF (RS)-E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH - CHME]
title_short THE ASYMMETRIC-SYNTHESIS OF BETA-LACTAMS - STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND SUBSEQUENT ALKYLATIONS OF E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH=CHME] - X-RAY CRYSTAL-STRUCTURE OF (RS)-E-[(ETA-5-C5H5)FE(CO)(PPH3)COCH - CHME]
title_sort asymmetric synthesis of beta lactams stereocontrolled asymmetric tandem michael additions and subsequent alkylations of e eta 5 c5h5 fe co pph3 coch chme x ray crystal structure of rs e eta 5 c5h5 fe co pph3 coch chme
work_keys_str_mv AT daviess theasymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT dordorhedgecocki theasymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT suttonk theasymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT walkerj theasymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT jonesr theasymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT proutk theasymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT daviess asymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT dordorhedgecocki asymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT suttonk asymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT walkerj asymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT jonesr asymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme
AT proutk asymmetricsynthesisofbetalactamsstereocontrolledasymmetrictandemmichaeladditionsandsubsequentalkylationsofeeta5c5h5fecopph3cochchmexraycrystalstructureofrseeta5c5h5fecopph3cochchme