Mixed Alkylamido Aluminate as a Kinetically Controlled Base.
The mechanisms by which directed ortho metalation (DoM) and postmetalation processes occur when aromatic compounds are treated with mixed alkylamido aluminate i-BuAI(TMP)Li (TMP-aluminate 1; TMP = 2,2,6,6-tetramethylpiperidide) have been investigated by computation and X-ray diffraction. Sequential...
| Publicado en: | Journal of the American Chemical Society Vol. 130; no. 48; pp. 16193 - 16201 |
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| Autores principales: | , , , , , , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
12/3/2008
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=35756757&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 35756757 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 12/3/2008 vid: 130 iid: 48 pid: 997 pub: American Chemical Society artinfo: ui: 35756757 10.1021/ja804749y ppf: 16193 ppct: 8 formats: tig: atl: Mixed Alkylamido Aluminate as a Kinetically Controlled Base. aug: au: Naka, Hiroshi Morey, James V. Haywood, Joanna EisIer, Dana J. McPartIin, Mary García, Felipe Kudo, Hironaga Kondo, Yoshinori Uchiyama, Masanobu WheatIey, Andrew E. H. affil: Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai 980-8578, Japan Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K. Advanced Elements Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan su: Aromatic compounds Aluminates Aluminum compounds Chemistry Optical diffraction sug: subj: Aromatic compounds Aluminates Aluminum compounds Chemistry Optical diffraction ab: The mechanisms by which directed ortho metalation (DoM) and postmetalation processes occur when aromatic compounds are treated with mixed alkylamido aluminate i-BuAI(TMP)Li (TMP-aluminate 1; TMP = 2,2,6,6-tetramethylpiperidide) have been investigated by computation and X-ray diffraction. Sequential reaction of ArC(=O)N(i-Pr) (Ar = phenyl, 1 -naphthyl) with t-BuLi and i-BuAI in tetrahydrofuran affords [2-(i-BuAI)CHC(=O)N(i-Pr)]Li+3THF (m = 6, n = 4, 7; m = 10, n = 6, 8). These data advance the structural evidence for ortho-aluminated functionalized aromatics and represent model intermediates in DoM chemistry. Both 7 and 8 are found to resist reaction with HTMP, suggesting that ortho-aluminated aromatics are incapable of exhibiting stepwise deprotonative reactivity of the type recently shown to pertain to the related field of ortho zincation chemistry. Density functional theory calculations corroborate this view and reveal the existence of substantial kinetic barriers both to one-step alkyl exchange and to amido-alkyl exchange after an initial amido deprotonation reaction by aluminate bases. Rationalization of this dichotomy comes from an evaluation of the inherent Lewis acidities of the Al and Zn centers. As a representative synthetic application of this high kinetic reactivity of the TMP-aluminate, the highly regioselective deprotonative functionalization of unsymmetrical ketones both under mild conditions and at elevated temperatures is also presented. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2008 holdings: @attributes: islocal: N |
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