Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• and thus the hydrogen-abstracting activity of N-oxyl, respectively. Unfortunately, it is not easy to modify the structure of N-hydroxyimides. A step forward in the development of N-oxyl-catalyzed transformations was made with the introduction of a new catalyst type, N-hydroxybenzimidazoles [84]. The N

Hypervalent iodine compounds for anti-Markovnikov-type iodo-oxyimidation of vinylarenes

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Mikhail A. Syroeshkin,
• Alexander A. Korlyukov,
• Pavel V. Dorovatovskii,
• Yan V. Zubavichus,
• Gennady I. Nikishin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188

• . It was shown that the iodine atom in the prepared iodo-oxyimides can be substituted by various nucleophiles. Keywords: free radicals; hypervalent iodine; imide-N-oxyl radicals; iodination; N-hydroxyimides; oxidative functionalization; Introduction The presented work opens a new chapter in the

• chemistry of N-hydroxyimides in combination with hypervalent iodine compounds with formation of imide-N-oxyl radicals. These radicals were used as reagents for the addition to a terminal position of the double bond of styrenes with subsequent iodination of the resulting benzylic radical. It is important to

• double bond. Results and Discussion In the present work, the reaction of styrenes 1a–k and N-hydroxyimides 2a,b with the formation of iodo-oxyimidated products 3aa–ka, 3ab–db, 3fb, 3hb and 3kb was carried out (Scheme 2). The key feature of the developed process is the non-standard regioselectivity of the

Consecutive hydrazino-Ugi-azide reactions: synthesis of acylhydrazines bearing 1,5-disubstituted tetrazoles

• Angélica de Fátima S. Barreto,
• Veronica Alves dos Santos and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2017, 13, 2596–2602, doi:10.3762/bjoc.13.256

• groups into more complex molecules. In this respect, Dömling et al. have recently described the synthesis of α-hydrazino amides using N-hydroxyimides as the acid component in Ugi reactions [28]. As part of our continuing efforts in using consecutive multicomponent reactions to obtain novel molecules in a

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• cyclohexanecarbaldehyde 148b with arylalkyl ketones 151 under similar conditions resulted in α-acyloxy ketones 152 [144] (Scheme 30). The plausible mechanism includes the formation of tert-butyl peresters from the aldehydes. N-Hydroxyimides 154 are efficient OH-reagents in the coupling with aldehydes and primary alcohols

• involves the nucleophilic addition of N-hydroxyimides to aldehydes followed by the oxidation of the resulting adduct to form the activated ester. For example, the C–O coupling of aldehydes 153 with N-hydroxyimides 154 was carried out in the presence of the Bu4NHal/t-BuOOH system (Hal = I or Br) [145]. This

• method is applicable to the oxidative coupling of aldehydes 156 with hexafluoroisopropanol giving esters 157. One of the coupling components is added in a twofold excess (Scheme 31). A similar oxidative coupling reaction was performed with primary alcohols 158 as CH-reagents and N-hydroxyimides 154a,b