Synthesis of the first amine–dicarboxyboranes and their derivatives

Chemistry of α‐Aminoboronic Acids and their Derivatives

“…The C-methoxy-N-ethyliminium groups adjacent to boron undergo an unusual hydrolysis [116]. The synthetic sequence is outlined in Scheme 4.30.…”

[B(CO2H)4]− und [B(CNCH3)4]3+ – homoleptische Borkomplexe mit Carboxy‐ und Methylisocyanid‐Liganden

“…Ausgangsverbindungen für die Herstellung von Carboxyboranen sind die entsprechenden Cyano‐Derivate, die ethyliert und anschließend unter sauren Bedingungen hydrolysiert werden 1. 4–10 Ein weiterer Zugang zu Carboxy‐Bor‐Komplexen wie [(CF 3 ) 3 BCO 2 H] − 11, 12 und [1,12‐(HO 2 C) 2 B 12 H 10 ] 2− 13, 14 besteht in der Addition von Wasser an Borcarbonyle. Das einfachste Carboxyboratanion, [H 3 BCO 2 H] − , konnte bisher nicht erhalten werden; Salze mit dem Dianion, [H 3 BCO 2 ] 2− , sind aber bekannt und stabil 15.…”

Synthesis of Amine-dicyanohydroboranes, [Amine-bis(ethylnitrilium)hydroboron(2+)] Tetrafluoroborates, and Their Derivatives as Precursors of Amine-dicarboxyboranes

“…Potentiometric studies revealed that amine carboxyboranes, only moderately depending on the nature of the amine, are very weak acids (p K a ≥ 8), and in protonated form they are generally very poorly soluble in water. To approach the acidities of the carboxylic groups in amine carboxyboranes and in aliphatic carboxylic acids, several new types of compounds have been prepared in our laboratory with electron withdrawing substituents on the boron (A·BH(X)COOH, X = Br, , amines, ,, COOH, CN). In addition, the existence of a number of these new derivatives renders the extension of the investigation of these valuable biological activities to structure−activity relationship studies possible.…”