Stereospecific coordination ofl-hydroxyproline esters with triosmium clusters
Tóm tắt
The reactions of cluster (μ-H)Os3(CO)10(μ-OH) with ethyl and isopropyl esters ofl-oxyproline were studied. In the presence of Me3NO intermediate complex (μ-H)Os3(CO)9(μ-OH)L (L — isopropyl ester ofl-oxyproline) is formed, which slowly converts to the more stable cluster (μ-H)Os3(CO)9
$$\left\{ {\mu ,\eta ^2 } \right.--{\rm O}|\overline {CHCH_2 CH(COOPr^i )NH} \mathop C\limits^| \left. {H_2 } \right\}$$
. Cluster complexes containing chelate-bridging heterocycles were also obtained by heating (μ-H)Os3(CO)10(μ-OH) with esters ofl-oxyproline. In both cases, only one of the possible diastereomeric complexes (μ-H)Os3(CO)9
$$\left\{ {\mu ,\eta ^2 } \right.--{\rm O}|\overline {CHCH_2 CH(COOPr^i )NH} \mathop C\limits^| \left. {H_2 } \right\}$$
(R = Et, Pri) is formed, which indicates that the reactions are stereospecific. Based on analysis of Dreiding's models, an attempt to determine the absolute configuration of the obtained clusters was made.
Tài liệu tham khảo
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