Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• of hydrogen atom from TBHP with radical A. The interaction of hydrogen donors (R–H) with radical A or B generates C-centered radical C. Then two ways of reaction proceeding are possible: the interaction of alkene 99 with C-centered radical C or with tert-butylperoxy radical B leads to the formation

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• reactions allow the sustainable construction of C–C and C–N bonds using alcohols as hydrogen donors. In recent years, manganese complexes have been explored as efficient catalysts in these reactions. This review highlights the significant progress made in manganese-catalyzed C–C and C–N bond-formation

• as hydrogen donors and alkylating agents. In general, low-valent manganese complexes are used as pre-catalysts in this reaction and are activated using a strong base to generate the active amido complexes, which in turn activate the alcohols. Then, the formed dehydrogenation products, such as

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• hydrogenation or hydrogen transfer [40], electrocatalysis coupled with water oxidation [41], and sustained visible-light-induced photocatalysis [42]. Among the different strategies available, the use of a mild photocatalytic process involving hole-driven hydrogen transfer with hydrogen donors or hole scavengers

Halides as versatile anions in asymmetric anion-binding organocatalysis

• Lukas Schifferer,
• Martin Stinglhamer,
• Kirandeep Kaur and
• Olga García Macheño

Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145

• the cationic reactive species. Keywords: anion binding; asymmetric catalysis; halide anions; hydrogen donors; noncovalent interactions; Introduction Halogens and the respective anionic halides occupy an essential role in natural and chemical processes [1][2][3][4]. While in chemical syntheses

Photocatalyzed syntheses of phenanthrenes and their aza-analogues. A review

• Alessandra Del Tito,
• Havall Othman Abdulla,
• Davide Ravelli,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 1476–1488, doi:10.3762/bjoc.16.123

• conditions finally afforded the desired phenanthridine 8.7 in 90% yield [69]. Carbon-based radicals could be likewise generated via a C–H hydrogen-atom transfer path. As an example, ethers were used as hydrogen donors and underwent a C–H cleavage step promoted by a photogenerated tert-butoxyl radical. The so

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• and HEH act respectively as electron and hydrogen donors. The protocol was efficient for dehalogenations with bromine- and iodine-containing acetophenone derivatives (75–98% yields). However, it was much less efficient with chloro ketones (12–40% yields) and not effective with α-bromo esters and α

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• resonance flash photolysis (ESRFP) and CIDNP in various solvents, depending on the efficiency of the solvents as hydrogen donors [19]. More specifically, triplet state benzaldehyde (9) dissolved in an efficient hydrogen donor solvent can lead to an α-hydroxybenzyl radical (11) as the only detectable species

Synthesis of novel 13α-estrone derivatives by Sonogashira coupling as potential 17β-HSD1 inhibitors

• Ildikó Bacsa,
• Rebeka Jójárt,
• János Wölfling,
• Gyula Schneider,
• Bianka Edina Herman,
• Mihály Szécsi and
• Erzsébet Mernyák

Beilstein J. Org. Chem. 2017, 13, 1303–1309, doi:10.3762/bjoc.13.126

• semihydrogenation of internal alkynes may be achieved by two main catalytic methods: with molecular hydrogen using Lindlar’s catalyst [25][26] or by transfer hydrogenation with hydrogen donors [27][28]. Additionally, alkynes undergo reduction with diimide to produce cis-alkenes [29]. Li et al. carried out the

Bifunctional phase-transfer catalysis in the asymmetric synthesis of biologically active isoindolinones

• Antonia Di Mola,
• Maximilian Tiffner,
• Francesco Scorzelli,
• Laura Palombi,
• Rosanna Filosa,
• Paolo De Caprariis,
• Mario Waser and
• Antonio Massa

Beilstein J. Org. Chem. 2015, 11, 2591–2599, doi:10.3762/bjoc.11.279

• already discussed [21][22][23], the bifunctional nature of organocatalysts plays an important role in this reaction to attain satisfactory levels of enantioselectivity. The presence of additional hydrogen donors such as urea groups positively affected the enantioselectivity both in the presence of chiral

Synthesis of chiral N-phosphinyl α-imino esters and their application in asymmetric synthesis of α-amino esters by reduction

• Yiwen Xiong,
• Haibo Mei,
• Lingmin Wu,
• Jianlin Han,
• Yi Pan and
• Guigen Li

Beilstein J. Org. Chem. 2014, 10, 653–659, doi:10.3762/bjoc.10.57

• the past years [31][32][33][34][35]. They usually served as mild hydrogen donors, but the use of them also made the purification difficult at the same time. Hydrogen gas is a traditional reduction source [36] and silanes and boranes are also well documented as the choices of reduction reagents [37][38

From porphyrin benzylphosphoramidate conjugates to the catalytic hydrogenation of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin

• Marcos C. de Souza,
• Leandro F. Pedrosa,
• Géssica S. Cazagrande,
• Vitor F. Ferreira,
• Maria G. P. M. S. Neves and
• José A. S. Cavaleiro

Beilstein J. Org. Chem. 2014, 10, 628–633, doi:10.3762/bjoc.10.54

• levels of hydrogenation on the β-pyrrolic double bonds [12][13]. Most of these methods employ chemicals other than H2 as hydrogen donors to reduce porphyrins into chlorins [14][15][16][17][18]. In our case, we decided to investigate the extent of the direct catalytic hydrogenation with H2 over TPPF20 in

• the template TPPF20 to TPCF20 and TPIF20 is cleaner and also more straightforward than most of the methods employing chemicals other than H2 as hydrogen donors. So far, the results indicate that the reduction is facilitated in polar medium, such as mixtures of ethanol, DMF and triethylamine, and that

Electron and hydrogen self-exchange of free radicals of sterically hindered tertiary aliphatic amines investigated by photo-CIDNP

• Martin Goez,
• Isabell Frisch and
• Ingo Sartorius

Beilstein J. Org. Chem. 2013, 9, 437–446, doi:10.3762/bjoc.9.46

• the ground states of our sensitizers can neither function as electron donors nor as hydrogen donors, exchange reactions involving different amine-derived radicals, meaning the intermediacy of different types of radical pairs, are the only remaining explanation for the different exchange rate constants

Hydrogen bonding patterns in the cocrystals of 5-nitrouracil with several donor and acceptor molecules

• Reji Thomas,
• R. Srinivasa Gopalan,
• G. U. Kulkarni and
• C. N. R. Rao

Beilstein J. Org. Chem. 2005, 1, No. 15, doi:10.1186/1860-5397-1-15

• Figure 9. This is yet another example of a supramolecular assembly hosting acyclic pentamer clusters of water. [31][32][33][34][35][36] The tetrahedral pentameric unit corresponds exactly to that described by Walrafen,[37][38] involving a central H2O molecule where the two hydrogen donors of the central