Organotrifluoroborates: Another Branch of the Mighty Oak

Abstract

Over the past two decades, organotrifluoroborates have evolved from being chemical curiosities to important reagents for the elaboration of organic molecules. Aside from their often-unique reactivity patterns, favorable features of these reagents include their ease of preparation/isolation, reliable crystallinity, enhanced stability, and monomeric structure. Currently >600 structurally diverse reagents of this class are commercially available, and >850 such compounds have been reported from the author's laboratory. The organotrifluoroborates can be utilized as shelf-stable precursors to a variety of end products through simple functional group transformations and have also been employed as partners in cross-coupling reactions between aromatic, alkenyl, alkynyl, and alkyl substrates in library or individual formats. Within the realm of cross-coupling reactions, organotrifluoroborates provide a practical entry to substructural entities not readily accessed using other organometallic reagents, and most recently, the development of a novel mechanistic paradigm for cross-coupling promises to expand the range of accessible cross-coupling partners even further to include both single- and two-electron processes.

Copper-mediated N-arylation of methyl 2-aminothiophene-3-carboxylate with organoboron reagents

“…The role of water in aryltrifluoroborate cross-couplings has been well documented. 31–35 Thus, water is normally required to hydrolyze the trifluoroborates to the boronic acids, the former thus serving as a stable reservoir for the more reactive boronic acid analogues. In this manner, bench stable aryltrifluoroborates were successfully cross-coupled with 2-aminothiophene-3-carboxylate ( 1 ) (Table 2).…”

Recent advances in dual transition metal–visible light photoredox catalysis

“…Due to their high stability and storability wide application was achieved. 27 In a Ni transition metal merged Ir photocatalyzed coupled system, a wide variety of (hetero)aryl bromides were coupled with subtituated benzyl BF 3 K salts, 26,28 secondary alkyl trifluoroboates, 29 α-alkoxymethyltrifluoroborates, 30 Bocprotected N-trifluoroboratomethyl amino acids 31 and aryl or aralkyl acyl chlorides with α-alkoxymethyltrifluoroborates. 32 In 2016, the synthesis of 1,1-diaryl-2,2,2-trifluoroethanes (16) were investigated by Molander and his co-workers (Figure 6).…”

Regioselective Diversification of 2,1-Borazaronaphthalenes: Unlocking Isosteric Space via C–H Activation

“…This would present an alternative approach to those employing an electrophilic , brominated core, opening up a wide array of complementary transformations. 5 One major drawback to most classical methods for installing nucleophilic coupling partners is that they are often derived from the corresponding halides, effectively passing through the electrophilic coupling partner in an inefficient synthetic pathway. A direct C–H borylation would circumvent that limitation and would lead directly to a readily diversifiable handle on the azaborine core.…”