Synthesis and reactivity of propionitrilium derivatives of cobalt and iron bis(dicarbollides)

Abstract

Synthesis of propionitrilium derivative of cobalt and iron bis(dicarbollides) [8-EtC≡N-3,3’-M(1,2-C2B9H10)(1’,2’-C2B9H11)] (M = Co, Fe) by the reaction of the cesium salts of the parent bis(dicarbollide) anions [3,3’-M(1,2-C2B9H11)2]- with propionitrile in...

Synthesis of Boronated Amidines by Addition of Amines to Nitrilium Derivative of Cobalt Bis(Dicarbollide)

“…Amidines 1-6 were obtained as mixtures of E and Z isomers in nearly quantitative yields. The formation of E and Z isomers was earlier observed for cobalt bis(dicarbollide) based imidates and thioimidates [51]. For the imidates with short alkoxy substituent such as methoxy and ethoxy, it was possible to separate isomers by column chromatography on silica.…”

“…This prompted us to study in more detail the reactions of nitrilium derivatives of cobalt bis(dicarbollide) with various primary and secondary amines. The propionitrilium derivative of cobalt bis(dicarbollide) [51] was chosen for this study due to clear identification of ethyl group in NMR spectra and, first of all, in 1 H NMR.…”

“…], the presence of even weaker NH•••HB contact (2.31 Å) leads to additional stabilization of the cisoid conformation by ~2 kcal mol −1 [51]. Therefore, for the amidines, a more significant stabilization of the cisoid conformation can be expected, especially in the case of compound 9.…”

“…Recently, we initiated a systematic study of nucleophilic addition reactions to the activated triple bond of nitrilium derivatives of cobalt bis(dicarbollide) and described the synthesis of a series of imidates and thioimidates based thereof [51]. In this contribution, we report on the synthesis of boronated amidines by nucleophilic addition of primary and secondary amines to the propionitrilium derivative of cobalt bis(dicarbollide).…”

New Method for Synthesis of Substituted N-Borylated Dipeptides Based on Acetonitrile Derivative of the closo-Dodecaborate Anion

“…It was previously shown that the addition of nucleophilic reagents of various natures to nitrile functional groups in anionic boron clusters can be considered as a convenient way of directed synthesis of their substituted derivatives [12][13][14][15][16][17][18][19][20][21][22][23][24], including those based on biologically active substances [6,25] and biomimetic systems [26,27]. It was found that the addition of tertbutyl esters of proteinogenic amino acids to nitrile derivatives of the closo-decaborate anion and their subsequent selective hydrolysis is a convenient method for the preparation of N-borylated peptides [28].…”