A Strategy for Selective Catalytic B–H Functionalization of o-Carboranes

Abstract

Ir-catalyzed selective B(3,6)-diborylation or B(3)-borylation of ocarboranes led to the synthesis of a series of 3,6-(Bpin) 2 -ocarboranes or 3-Bpin-o-carboranes in very high yields and excellent regioselectivity.

Electrochemical Cage Activation of Carboranes

“…In recent years, the transition‐metal‐catalyzed B−H functionalization of o ‐carborane has witnessed major momentum, with a strong incentive being the synthesis of new o ‐carborane‐containing materials and drug molecules; this has been summarized in a recent review [30] . However, most of the established oxidation reactions require noble transition metal catalysts and an excess amount of chemical oxidants, which compromises the resource economy [13, 14] .…”

“…In recent years, the transition-metal-catalyzed BÀ H functionalization of o-carborane has witnessed major momentum, with a strong incentive being the synthesis of new ocarborane-containing materials and drug molecules; this has been summarized in a recent review. [30] However, most of the established oxidation reactions require noble transition metal catalysts and an excess amount of chemical oxidants, which compromises the resource economy. [13,14] In sharp contrast, the combination of base-metal catalysis and electrochemistry for the BÀ H functionalization of carboranes represents an attractive and environmentally friendly alternative to traditional methods, and avoids the use of harsh oxidizing agents and noble transition metal catalysts (Scheme 7).…”

Elektrochemische Carborankäfig‐Aktivierung

“…In den letzten Jahren hat die Übergangsmetall-katalysierte Funktionalisierung von o-Carboranen einen großen Aufschwung erlebt und stellt nun einen starken Anreiz für die Synthese neuer o-Carboran-haltiger Materialien und Pharmazeutika dar, was kürzlich in einem Übersichtsartikel zusammengetragen wurde. [30] Die meisten herkömmlichen Oxidationsreaktionen erfordern teure Edelmetallkatalysatoren und einen Überschuss an chemischen Oxidationsmitteln, was die Ressourcenschonung enorm verringert. [13,14] Im Gegensatz dazu ist die metalla-elektrokatalysierte BÀ H-Funktionalisierung von Carboranen eine attraktive und umwelt-freundliche Alternative, die ohne den Einsatz von starken Oxidationsmitteln und teuren Edelmetallkatalysatoren auskommt (Schema 7).…”

Regioselectivity of Pd-catalyzedo-carborane arylation: a theoretical view

“…[31][32][33] The most challenging factor in broadening the applications of carboranes is the ability to perform selective functionalizations at the desired B-H or C-H vertex. 19,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] In order to give a glance of icosahedral carboranes, the number system of dicarba-closo-dodecarboranes (C 2 B 10 H 12 ) has been shown in Scheme 1(a). The electrostatic potential (ESP) surface calculation of o-carborane reveals charge separation character (Scheme 1(b)), wherein the positive charge resides mainly on B-H bonds and the negative charge resides mainly on C-H bonds.…”