Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• catalyst to produce radicals at the 2- and 5-positions of thiophene and synthesized four types of poly(3-alkylthiophene)s (PATs) with different linking ways (Scheme 10). 2.2 Polymerization by thiol–ene chemistry The thiol–ene reaction (also called alkene hydrothiolation) is the anti-Markovnikov addition of

• a thiol to a C–C double bond and was first reported in 1905 [80]. It is considered as a click chemistry reaction due to its high yield, stereoselectivity, rate, and thermodynamic driving force. Generally, the thiol–ene reaction is conducted under radical conditions, often photochemically induced [81

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• 105–109 (Scheme 40) [73]. 3.5 Other synthetic routes to β-hydroxy sulfides Incorporation of amine, silyl and sulfide functional groups into C–C multiple bonds offers an attractive route to appropriately functionalized substrates. Inter- and intramolecular thiol-ene reaction is a highly efficient, free

• -radical mediated “click” process with diverse applications in small molecule and polymer synthesis and has been reviewed [74][75][76]. The importance of the thiol-ene reaction in the synthesis of β-hydroxy sulfides is exemplified by the work of Scanlan and co-workers as shown in Scheme 41 [77][78

• alkenes. Proposed catalytic cycle for asymmetric sulfenofunctionalization. Synthesis of thiosugars using intramolecular thiol-ene reaction. Synthesis of leukotriene C-1 by Corey et al.: (a) N-(trifluoroacetyl)glutathione dimethyl ester (3 mol equiv), Et3N, MeOH, 23 °C, 4 h, 80%; (b) K2CO3 (0.1 M) in H2O

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• preparation of sulfides. Non-photocatalytic procedures apply the so-called radical thiol–ene or radical thiol–yne reactions for efficient cross-coupling of thiols with olefins [24][29][30]. In 2013, Yoon and co-workers developed a photoredox-catalyzed version of the radical thiol–ene reaction (Scheme 2) [31

• , which was applied to their photocatalytic radical thiol-ene reaction (Scheme 3) [32]. While the photooxidation of aliphatic thiols by excited [Ru(bpz)3](PF6)2 is thermodynamically feasible, this process is kinetically hindered. Therefore, relatively low yields are observed or the amount of thiol has to

• photoredox-catalyzed radical thiol–ene reaction for polymer postfunctionalization and step-growth addition polymerization (Scheme 4a) [33]. In contrast to Yoon’s conditions, they used [Ru(bpy)3]Cl2 as photocatalyst and N-methyl-2-pyrrolidone as solvent and were able to efficiently couple polybutadiene and

Synthesis and evaluation of anti-oxidant and cytotoxic activities of novel 10-undecenoic acid methyl ester based lipoconjugates of phenolic acids

• Naganna Narra,
• Shiva Shanker Kaki,
• Rachapudi Badari Narayana Prasad,
• Sunil Misra,
• Koude Dhevendar,
• Venkateshwarlu Kontham and
• Padmaja V. Korlipara

Beilstein J. Org. Chem. 2017, 13, 26–32, doi:10.3762/bjoc.13.4

• methyl 10-undecenoate which was subjected to a thiol–ene reaction with cysteamine hydrochloride. Further amidation of the amine was carried out with different phenolic acids such as caffeic, ferulic, sinapic, coumaric and cinnamic acid. All synthesized compounds were fully characterized and their

• lipoconjugates of phenolic acids is reported. The synthetic route was simple with product yields in the range of 84–86% over three steps. The lipid part, methyl 10-undecenoate was subjected to a thiol–ene reaction with cysteamine hydrochloride and the resulting intermediate was conjugated with the phenolic acid

Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid

• Federica Santoro,
• Matteo Mariani,
• Federica Zaccheria,
• Rinaldo Psaro and
• Nicoletta Ravasio

Beilstein J. Org. Chem. 2016, 12, 2627–2635, doi:10.3762/bjoc.12.259

• reaction of optically active (R)-1-phenylethanol gave a completely racemic compound (Scheme 1). Unfortunately allylic alcohols gave unreproducible results. However, in the case of cinnamyl alcohol (1i) we could obtain a fairly good selectivity to the product of the thiol–ene reaction 3p (Scheme 2). The

Postsynthetic functionalization of glycodendrons at the focal point

• Thisbe K. Lindhorst and
• Katharina Elsner

Beilstein J. Org. Chem. 2014, 10, 1482–1487, doi:10.3762/bjoc.10.152

• etherification, thiol-ene reaction and in particular olefin cross metathesis. Keywords: amphiphilic glycomimetics; cross metathesis; glycodendrons; multivalent glycoconjugates; multivalent glycosystems; Introduction In addition to nucleic acids and proteins, molecular life is based on a third important class

• expected in case of the glycodendrons 3–9. However, the so-called “thiol-ene” reaction [10] gave reliable results with both bivalent and tetravalent glycodendrons. The radical addition of mercaptododecane to either 3 or 7, employing AIBN as radical starter, led to the amphiphilic thioethers 12 and 13

• ). Conclusion In conclusion, it was shown that readily available polyether glycodendrons can be refined employing suitable postsynthetic modification of the focal point. We have illustrated, that alkylation, thiol-ene reaction and in particular olefin cross metathesis leads to di- and tetravalent glycolipid

Combined bead polymerization and Cinchona organocatalyst immobilization by thiol–ene addition

• Kim A. Fredriksen,
• Tor E. Kristensen and
• Tore Hansen

Beilstein J. Org. Chem. 2012, 8, 1126–1133, doi:10.3762/bjoc.8.125

• water and copolymerized on heating by thiol–ene additions. The resultant spherical and gel-type polymer beads have been evaluated as organocatalysts in catalytic asymmetric transformations. Keywords: asymmetric catalysis; Cinchona derivatives; organocatalysis; polymerization; thiol–ene reaction

• of thiol and alkene functionalities was adjusted to be close to unity, and the thiol–ene reaction usually has a high degree of conversion; however, the presence of free thiol groups is probably unavoidable. We were, nevertheless, curious to investigate how these supported organocatalysts would