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 (JACS2003, 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:
"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