羧酸衍生物与不对称铼π碱的二配位：酰胺异构化的新机制？

Dihapto coordination of carboxylic acid derivatives with an asymmetric rhenium pi-base: a new mechanism for amide isomerization?

作者信息

Meiere Scott H, Ding Fei, Friedman Lee A, Sabat Michal, Harman W Dean

机构信息

Department of Chemistry, University of Virginia, Charlottesville 22901, USA.

出版信息

J Am Chem Soc. 2002 Nov 13;124(45):13506-12. doi: 10.1021/ja011497v.

DOI:10.1021/ja011497v

PMID:12418904

Abstract

The asymmetric pi basic metal fragment [TpRe(CO)(MeIm)] (Tp = hydridotris(pyrazolyl)borate, MeIm = 1-methylimidazole) forms thermally stable complexes with ethyl acetate, acetic anhydride, N-methylsuccinimide, N-acetylpyrrole, and N-methylmaleimide in which the metal binds a carbonyl group in a pi fashion. In all cases a single diastereomer is observed, indicating that one enantioface of the carbonyl is selectively coordinated. X-ray and NMR data for the compound TpRe(CO)(MeIm)(eta(2)-N-methylsuccinimide) indicate that metal coordination effectively removes the pi interaction between the bound carbonyl and the nitrogen of the succinimide ring.

摘要

不对称π-碱金属片段[TpRe(CO)(MeIm)]（Tp = 氢化三（吡唑基）硼酸酯，MeIm = 1-甲基咪唑）与乙酸乙酯、乙酸酐、N-甲基琥珀酰亚胺、N-乙酰基吡咯和N-甲基马来酰亚胺形成热稳定配合物，其中金属以π方式结合羰基。在所有情况下，均观察到单一非对映异构体，这表明羰基的一个对映面被选择性配位。化合物TpRe(CO)(MeIm)(η²-N-甲基琥珀酰亚胺)的X射线和核磁共振数据表明，金属配位有效地消除了配位羰基与琥珀酰亚胺环氮之间的π相互作用。