Copper-catalyzed radical trans-selective hydroboration of ynamides with N-heterocyclic carbene boranes

Radical hydroboration for the synthesis of organoboron compounds

“…Later, copper-catalysed radical hydroboration of N -sulfonyl-arylynamides 31 with NHC–borane 2 was disclosed by the group of Xu and Wang (Scheme 8). 39 The ynamide structure of 31 partly existed as its keteniminium resonance intermediate A in the reaction system. Meanwhile, in the presence of potassium tert -butoxide as the base, a borenium ion with hydridic properties was obtained to attack the electrophilic α-carbon of A , resulting in the formation of a new borenium ion and anionic B .…”

An Overview of the Synthesis of Hexafluoroisopropanol and Its Key Intermediates

“…1 The presence of two tri-fluoroalkyl groups in HFIP is thought to significantly alter the course of chemical reactions and plays a huge role in traditional organic synthesis, 2 electrocatalysis, 3 photocatalysis, 4 biological research, 5 and even environmental science. 6 HFIP is also a very popular solvent and additive for the activation of hydrogen peroxide, 7 organic functionality, 8 hypervalent iodine reagents, 9 metal-free C-H, 10 etc., due to its strong polarity, recyclability, hydrogen bond donor nature, as well as its low nucleophilicity, high acidity, cationic stabilizing ability, easy intermiscibility with water and many organic reagents, 11,12 heat resistance, and allowance for the passage of ultraviolet (UV) light. The solvent together with trifluoroethanol provides an excellent reaction system for many of the classical organic transformations and can be used to achieve catalyst-free systems.…”

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“…1 The presence of two tri-fluoroalkyl groups in HFIP is thought to significantly alter the course of chemical reactions and plays a huge role in traditional organic synthesis, 2 electrocatalysis, 3 photocatalysis, 4 biological research, 5 and even environmental science. 6 HFIP is also a very popular solvent and additive for the activation of hydrogen peroxide, 7 organic functionality, 8 hypervalent iodine reagents, 9 metal-free C-H, 10 etc., due to its strong polarity, recyclability, hydrogen bond donor nature, as well as its low nucleophilicity, high acidity, cationic stabilizing ability, easy intermiscibility with water and many organic reagents, 11,12 heat resistance, and allowance for the passage of ultraviolet (UV) light. The solvent together with trifluoroethanol provides an excellent reaction system for many of the classical organic transformations and can be used to achieve catalyst-free systems.…”