Tin-Free Giese Reaction and the Related Radical Carbonylation Using Alkyl Iodides and Cyanoborohydrides

Abstract

Tin-free Giese reaction and the related radical carbonylation process proceeded efficiently in the presence of sodium cyanoborohydride and tetrabutylammonium cyanoborohydride. The reaction took place chemoselectively at the carbon-iodine bond but not at the carbon-bromine and carbon-chlorine bonds. The iodine atom transfer followed by hydride reduction of the resulting carbon-iodine bond is proposed as a possible mechanism.

Ex Vivo Oxidation in Tissue and Plasma Assays of Hydroxyoctadecadienoates: Z,E/E,E Stereoisomer Ratios

“…Reduction of alkyl mercurials is attended by free radical reactions of intermediate carbon radicals with molecular oxygen and free radical mechanisms have been written for the reaction of the reducing agent with alkyl halides as well. (49-52) The borohydride ion has been proposed to be a source of hydrogen atoms with the radical anion of BH 3 as a chain-propagating intermediate.…”

Free‐Radical Multicomponent Processes

“…Tin-free Giese reaction has been developed relying on this useful reactivity of CO [60]. Reaction of iodide 85 with acrylate 84 in the presence of CO (90 atm) and n-Bu 4 NBH 3 CN led to the formation of the keto ester 86 in satisfying yield (Scheme 14.20, (1)).…”

One-pot synthesis of cyanohydrin derivatives from alkyl bromides via incorporation of two one-carbon components by consecutive radical/ionic reactions

“…Under the reaction conditions where a catalytic amount of fluorous tin hydride and an excess amount of sodium cyanoborohydride were used, initially formed aldehydes can be converted into hydroxymethylated compounds in one-pot [7–9], since borohydride acts not only as the reagent for the regeneration of tin hydride [10–13] but also as the reagent for aldehyde reduction. Later on we found that borohydride reagents can also serve as radical mediator delivering hydrogen to the radical centre [14], thus we developed a hydroxymethylation method using Bu 4 NBH 4 and a radical initiator [15–17]. Recent work in collaboration with Dennis Curran has revealed that, with the use of NHC-borane [18], hydroxymethylation of aromatic iodides can be attained [19].…”