Electrochemical B−H Nitrogenation: Access to Amino Acid and BODIPY‐Labeled nido‐Carboranes

Abstract

Electrocatalyzed oxidative B À H nitrogenations of nido-carborane (nido-7,8-C 2 B 9 H 12 À) with N-heterocycles have been established, enabling the preparation of various Nsubstituted nido-carboranes without chemical oxidants or metal catalyst under ambient conditions. The electrolysis manifold occurred with high levels of efficiency as well as chemo-and position-selectivity, employing sustainable electricity as the sole oxidant. The strategy set the stage for a userfriendly access to novel amino acid and fluorogenic borondipyrrin (BODIPY)-labeled nido-carborane hybrids.

Electrooxidative B−H Functionalization of nido‐Carboranes

“…According to our previous study using DDQ as the oxidant [12] and literature reports, [22] as well as in combination of the deuterium labelling experiment and cyclic voltammetry measurements,aplausible mechanism for the electrooxidative BÀSbond formation between nido-carborane and diethyl sulfide was proposed in Figure 4. nido-Carborane is oxidized…”

“…Apart from aliphatic thioethers,t he reactivity of aryl thioethers were also investigated. Moderate yields were observed for thioethers with one aryl group (17)(18)(19)(20)(21)(22)(23). But diphenyl sulfide was unreactive under the same electrolytic conditions (9), which is likely caused by the conjugation of the phenyl rings with the lone pair of sulfur atom.…”

Electrooxidative B−H Functionalization of nido‐Carboranes

“…According to our previous study using DDQ as the oxidant [12] and literature reports, [22] as well as in combination of the deuterium labelling experiment and cyclic voltammetry measurements, a plausible mechanism for the electrooxidative B−S bond formation between nido ‐carborane and diethyl sulfide was proposed in Figure 4. nido ‐Carborane is oxidized by anode through two single electron transfer processes to afford a cationic intermediate II.…”

Elektrochemische B‐H‐Nitrogenierung: Zugang zu Aminosäure‐ und BODIPY‐markierten nido‐Carboranen

“…Die Konnektivitätd er Produkte (3an und 3aw)w urde mittels Rçntgen-Einkristall-Beugungsanalyse eindeutig verifiziert. [23] Motiviert durch die einzigartige Effizienz der elektrokatalysierten metallfreien oxidativen B-N-Kupplung mit verschiedenen N-heterocyclischen Substraten wollten wir die post-synthetische Aminosäure-und BODIPY-Diversifikation der strukturell komplexen nido-Carborane erforschen (Schema 2). Sowohl Aminosäure-als auch BODIPY-markierte Pyridine erwiesen sich als geeignete Substrate (5aa-5ad).…”

“…Darüber hinaus wurde die Molekularstruktur der Produkte (5ac und 7b)e rneut eindeutig durch Einkristall-Rçntgenbeugung verifiziert. [23] Tabelle 1: Optimierung der Reaktionsbedingungen. [a] Eintrag Elektrolyt Lçsungsmittel Ausbeute[%] [b] [21] (Schema 4).…”