Highly Stereoselective Formation of Cp*IrCl Complexes of N,N-Dimethylamino Acids
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- 作者：Douglas B. Grotjahn ; Camil Joubran ; and John L. Hubbard
- 刊名：Organometallics
- 出版年：1996
- 出版时间：February 20, 1996
- 年：1996
- 卷：15
- 期：4
- 页码：1230 - 1235
- 全文大小：253K
- 年卷期：v.15,no.4(February 20, 1996)
- ISSN：1520-6041
文摘
N,N-Dimethylamino acids serve as (N,O)-chelating monoanionic ligands to the prochiralfragment Cp*IrCl. A series of four such complexes and one Rhanalog all were formed withdiastereoselectivity of 
50:
1. The structure of the valinecomplex 5d(C17H29ClIrNO2)wasanalyzed at 298 K, from which a cis-arrangement of Cp* and valine sidechain (i-Pr) wasrevealed. Solution NMR studies of 5d, aided by anunusual zero coupling between the twomethine protons of the amino acid, showed that the structures insolution and the solidwere very similar. The preference for the cis-oriented Cp* andamino acid side chain in 5is attributed to a maximum number of gauche interactions in themetallacycle and itssubstituents, especially pronounced for N,N-disubstituted amino acids.
50:1. The structure of the valinecomplex 5d(C17H29ClIrNO2)wasanalyzed at 298 K, from which a cis-arrangement of Cp* and valine sidechain (i-Pr) wasrevealed. Solution NMR studies of 5d, aided by anunusual zero coupling between the twomethine protons of the amino acid, showed that the structures insolution and the solidwere very similar. The preference for the cis-oriented Cp* andamino acid side chain in 5is attributed to a maximum number of gauche interactions in themetallacycle and itssubstituents, especially pronounced for N,N-disubstituted amino acids.