Organocatalysis
The Michael addition between thiols and electron-poor olefins is categorized as a click reaction and finds wide application in polymer and materials chemistry in particular in its nucleophile mediated variant. Strasser and Slugovc became interested whether it is feasible to use less acidic and less nucleophilic alcohols instead of thiols. Using alcohols would be desirable for several reasons: alcohols are more readily available than thiols and thiols exhibit inherent drawbacks such as their tendency to form disulfides, their (often) bad odor and toxicity.
The work by Bergman and Toste (JACS 2003, 125, 8696) on phosphine-initiated hydroalkoxylation of α,β-unsaturated ketones paved the way for studying and using the oxa-Michael reaction in organic chemistry. The application of their findings in polymer and materials chemistry, however, is scarce.
A recent communication from us demonstrates that the nucleophile mediated oxa-Michael reaction between alcohols and divinyl sulfone is particularly fast and efficient under solvent-free conditions allowing for the preparation of polymers. Interestingly the presence of water is tolerated in such reactions.
The findings prove the chance to invent a whole new class of polymeric materials based on electron-poor olefins and alcohols as the monomeric building blocks.
For further reading see:
"Synthesis, characterization and stability of phosphonium phenolate zwitterions derived from a (diphenylphosphino)phenol derivative and oxiranes."
Steiner, M. R.; Marschner, C.; Baumgartner, J.; Hlina, J. A.; Slugovc, C. Monatsh. Chem. 2024, 155, 715-723. DOI: 10.1007/s00706-024-03216-1
"Using the phospha-Michael reaction for making phosphonium phenolate zwitterions."
Steiner, M. R.; Schmallegger, M.; Donner, L.; Hlina, J. A.; Marschner, C.; Baumgartner, J.; Slugovc, C. Beilstein J. Org. Chem. 2024, 20, 41–51. DOI: 10.3762/bjoc.20.6
"Functionalized electron-rich pyridines as initiators for the epoxy homopolymerization."
Edinger D.; Fischer, S. M.; Slugovc, C. Macromol. Chem. Phys. 2024, 225, 2300299. DOI: 10.1002/macp.202300299
"Poly(ether)s derived from oxa-Michael polymerization - A comprehensive review."
Ratzenböck, K.; Fischer, S. M.; Slugovc, C. Monatsh. Chem. 2023, 154, 443-458. DOI: 10.1007/s00706-023-03049-4
"Sequential dual-curing of electron-deficient olefins and alcohols relying on oxa-Michael addition and anionic polymerization"
Fischer, S. M.; Schallert, V.; Uher, J. M.; Slugovc, C. Polym. Chem. 2023, 14, 1081-1084. DOI: 10.1039/D3PY00035D
"Exploiting retro oxa-Michael chemistry in polymers."
Ratzenböck, K.; Uher, J. M.; Fischer, S. M.; Edinger, D.; Schallert, V.; Žagar, E.; Pahovnik, D.; Slugovc, C. Polym. Chem. 2023, 14, 651-661. DOI: 10.1039/D2PY01345B
"Tris(2,4,6-trimethoxyphenyl)phosphine - a Lewis base able to compete with phosphazene bases in catalysing oxa-Michael reactions."
Fischer, S. M.; Kaschnitz, P.; Slugovc, C. Catal. Sci. Technol. 2022, 12, 6204-6212. DOI: 10.1039/D2CY01335E
"Water as a monomer: synthesis of an aliphatic polyethersulfone from divinyl sulfone and water."
Ratzenböck, K.; Din, M. M. U.; Fischer, S. M.; Žagar, E.; Pahovnik, D.; Boese, A. D.; Rettenwander, D.; Slugovc, C. Chem. Sci. 2022, 13, 6920-6928. DOI: 10.1039/D2SC02124B
"Electron-rich triarylphosphines as nucleophilic catalysts for oxa-Michael reactions."
Fischer, S. M.; Renner, S.; Boese, A. D.; Slugovc, C. Beilstein J. Org. Chem. 2021, 17, 1689–1697. DOI: 10.3762/bjoc.17.117
"Melt-polymerization of acrylamide initiated by nucleophiles: a route towards highly branched and amorphous polyamide 3."
Edinger, D.; Weber, H.; Žagar, E.; Pahovnik, D.; Slugovc, C. ACS Appl. Polym. Mater. 2021, 3, 2018-2026. DOI: 10.1021/acsapm.1c00084
"Step-growth polymerisation of alkyl acrylates via concomitant oxa-Michael and transesterification reactions."
Ratzenböck, K.; Pahovnik, D.; Slugovc, C. Polym. Chem. 2020, 11, 7476-7480. DOI: 10.1039/D0PY01271H
"Solvent‐ and catalyst‐free aza‐Michael addition of imidazoles and related heterocycles."
Kodolitsch, K.; Gobec, F.; Slugovc, C. Eur. J. Org. Chem. 2020, 19, 2973-2978. DOI: 10.1002/ejoc.202000309
"Solvent-free macrocyclisation by nucleophile-mediated oxa-Michael addition polymerisation of divinyl sulfone and alcohols."
Strasser, S.; Wappl. C.; Slugovc. C. Polym. Chem. 2017, 8, 1797-1804. DOI: 10.1039/C7PY00152E - see the feature for more information.
"Nucleophile-mediated oxa-Michael addition reactions of divinyl sulfone - a thiol-free option for step-growth polymerisations."
Strasser, S.; Slugovc, C. Catal. Sci. Technol. 2015, 5, 5091-5094. DOI: 10.1039/c5cy01527h
