Partners and International Organizations
(English)
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AT, BE, CH, CY, CZ, DE, DK, ES, FI, FR, GR, HR, HU, IL, IT, LT, PL, RO, RS, SE, TR, UK
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Abstract
(English)
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The general goal of this project was to develop highly efficient radical coupling reactions that fulfill the requirements for click reactions and to apply them for the preparation of labeled biomaterial and glycoconjugates. The phosphorous-ene coupling (PEC) reaction, has been selected for our investigation. Due to the nature of the phosphorous centered radicals, the reversibility of the initial addition step is slow and therefore efficient coupling reactions are expected. A number of different phosphorous reagents were tested and excellent results were obtained with diarylphosphine oxides (DAPO). With these compounds, efficient coupling with a wide range of alkenes were achieved in water using a 1:1 alkene/DAPO ratio. This reaction presents a unique potential for the preparation of bioconjugates and its compatibility with functional groups usually present in biological systems is currently tested. The thiol-ene coupling (TEC) reaction is a well-established procedures that fits the criteria of a click reaction. However, its efficiency is reduced when the alkene partner is a good hydrogen atom donor such as allyl ethers. To solve this problem, a procedure involving the use of 4-tert-butyl-catechol as an additive was developed. A detailed mechanistic investigation of this process has been performed. A unique repair mechanism involving thiols and catechols has been identified. Interestingly, this repair mechanism may be occurring in biological systems but has never been reported so far.
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