addition of isocyanocarboxylic acid esters the isocyanide complexes [(arene)M(CNCHR1CO2R2)3]2+(X−)2 (arene = C6Me6, p-cymene, M = Ru; arene = C5Me5, M = Rh, Ir), (R1 = H, Me, CHMe2, CH2Ph, X = BF4, CF3 SO3) were prepared and characterized. The structure of [(C5Me5) Ir(CNCH2CO2Et)3]2+(CF3SO3−)2 was determined by X-ray structure analysis.
通过氯桥连半夹心配合物与银盐的反应以及随后异氰基羧酸酯的加入,异氰化物配合物[(芳烃)M(CNCHR1CO2R2)3]2+(X-)2(芳烃=C6Me6,对伞花烃,M=Ru;芳烃 = C5Me5, M = Rh, Ir), (R1 = H, Me, CHMe2, CH2Ph, X = BF4, CF3 SO3) 被制备和表征。[(C5Me5) Ir(CNCH2CO2Et)3]2+( SO3-)2 的结构由 X 射线结构分析确定。
The Passerini reaction offers an easy access to depsipeptides, when both acid and isocyanide are derived from of.-amino acids. However, racemisation of isocyanides derived from alpha-amino acid esters severely limits their use in the Passerini reaction. In order to overcome this limitation, a study on the influence of the alpha-amino acid N-protecting group on the yield and diastereoisomeric ratio of the product of the Passerini reaction was performed. Six different protecting groups were tested. Their influence turns out to be crucial and is not constant when the amino acid is changed. After optimisation, the Passerini reaction products with cyclohexanone as the carbonyl component were obtained with 99% yield and >98% de. (C) 2008 Elsevier Ltd. All rights reserved.