Characterization of a chiral enolate aggregate and observation of 6Li-1H scalar coupling.
作者： Deyu Li , Chengzao Sun , Paul G. Williard
DOI: 10.1021/JA802114J
关键词:
摘要: A chiral enolate aggregate 1 containing a lithium and amide was systematically investigated by various NMR techniques. (1)H (13)C DOSY at 25 -78 degrees C provide its solution structure, aggregation number, formula weight. Multiple 2D (6)Li techniques, such as (6)Li-(6)Li EXSY, (6)Li-(1)H HOESY, were utilized to investigate stereochemical structure. The configuration of the in complex confirmed HOESY trapping with TMS-Cl. unique coupling through Li-N-C-H network observed. This scalar corroborated HMQC, deuterium labeling experiments, selective decoupling NMR. stereostructure provides model for origin enantioselectivity amide-induced addition reactions.
acs.org
sci-hub.se 参考文章(110)
Jeffrey S. DePue, David B. Collum, Structure and reactivity of lithium amides. Lithium-6, carbon-13, and nitrogen-15 NMR spectroscopic studies and colligative measurements of lithium diphenylamide and lithium diphenylamide-lithium bromide complex solvated by tetrahydrofuran Journal of the American Chemical Society. ,vol. 110, pp. 5518- 5524 ,(1988) , 10.1021/JA00224A041
Modern aldol reactions Wiley-VCH Verlag GmbH. ,(2004) , 10.1002/9783527619566
Organolithiums in enantioselective synthesis Springer Berlin Heidelberg. ,(2003) , 10.1007/3-540-36117-0
The chemistry of organolithium compounds John Wiley & Sons, Ltd. ,(2004) , 10.1002/047002111X
Jean-Paul Quintard, Marie Degueil-Castaing, Bernard Barbe, Michel Petraud, Interet de la deuteriation des molecules organostanniques en RMN de 119Sn : II. Relation de type karplus pour 3J(SnD) et stereochimie de deuteriostannation de quelques hydrocarbures ethyleniques Journal of Organometallic Chemistry. ,vol. 234, pp. 41- 61 ,(1982) , 10.1016/S0022-328X(00)85701-0
Steffen Schade, Gernot Boche, The effect of (poly)amine ligands on the solution structure of [6Li]-α-(phenylthio)benzyllithium in tetrahydrofuran: A 1H,6Li-HOESY NMR study1Dedicated to Professor Ken Wade on the occasion of his 65th birthday.1 Journal of Organometallic Chemistry. ,vol. 550, pp. 359- 379 ,(1998) , 10.1016/S0022-328X(97)00239-8
Patricia L. Hall, James H. Gilchrist, David B. Collum, Effects of lithium salts on the stereochemistry of ketone enolization by lithium 2,2,6,6-tetramethylpiperidide (LiTMP). A convenient method for highly E-selective enolate formation Journal of the American Chemical Society. ,vol. 113, pp. 9571- 9574 ,(1991) , 10.1021/JA00025A023
Hans-Egbert Mons, Harald Günther, Adalbert Maercker, NMR Spectroscopy of Organolithium Compounds, XV[1]. Two-Dimensional 6Li,1H-NMR Shift Correlation by Multiple Quantum Spectroscopy and Polarization Transfer: New Tools for Structural Research in the Field of Organolithium Compounds Chemische Berichte. ,vol. 126, pp. 2747- 2751 ,(1993) , 10.1002/CBER.19931261226
Lloyd M. Jackman, L. M. Scarmoutzos, C. W. DeBrosse, Lithium Quadrupole Coupling Constants and the Structures of Organic Lithium Compounds in Solution Journal of the American Chemical Society. ,vol. 109, pp. 5355- 5361 ,(1987) , 10.1021/JA00252A009
Zacharia A. Fataftah, Ihor E. Kopka, Michael W. Rathke, Role of HMPT and TMEDA in control of enolate stereochemistry for reactions of lithium amides with 3-pentanone Journal of the American Chemical Society. ,vol. 102, pp. 3959- 3960 ,(1980) , 10.1021/JA00531A052