Anionic five-coordinate complexes with two bis-O,O’-chelating ligands bearing α-hydroxy acid moieties, dicyclohexylammonium salts $$\text{Cy}_{2}\text{NH}_{2}{^+}\{\text{PpnCH}_2\text{Si}[\text{OCR}_2\text{C}\text{(O)O]}_2\}^-$$ Cy 2 NH 2 + { PpnCH 2 Si [ OCR 2 C (O)O] 2 } − (Cy is cyclohexyl, PpnCH2 is 4-methyl-2,5-dioxopiperazin-1-ylmethyl, R = Me, Ph), were synthesized by esterification of alkoxysilane PpnCH2Si(OMe)3 with α-hydroxy acids (dimethyl- and diphenylgylcolic acids) in the presence of dicyclohexylamine. The five-coordinated state of the silicon atom in the resulting compounds in solution was confirmed by 29Si NMR spectroscopy. According to the X-ray diffraction data, the synthesized compounds contain the SiCO4 coordination unit.