Readily accessible azido-alkyne-functionalized monomers for the synthesis of cyclodextrin analogues using click chemistry

Abstract

A set of linear and cyclic oligomers were synthesized starting from a suitable azido-alkyne monomer through click oligomerization. The synthesis of these monomers starting from bromobenzene features an enzymatic dihydroxylation...

Achievements, Challenges, and Scope of Thirty Years of Work on the Biotransformation of Arenes and Their Synthetic Applications

“…The product distribution of the oligomerization could be modulated by the monomer concentration and the use of additives. In this way, using the conditions shown in Scheme 37, cyclic oligomers can be obtained in 66% isolated yield, consisting of a mixture of tetramer 140a, pentamer 140 b, and hexamer 140 c. [122] This disclosure constitutes the first report on the preparation of cyclodextrin analogues based on non-sugar building blocks.…”

“…Thus, several azido alkyne monomers were prepared as substrates for the click oligomerization reaction, with those functionalities in either 1,3‐ or 1,4 relationship (Scheme 36). [122] …”

“…Thus, several azido alkyne monomers were prepared as substrates for the click oligomerization reaction, with those functionalities in either 1,3-or 1,4 relationship (Scheme 36). [122] Monomers 135, 136, and 137 can be used in the direct click oligomerization (direct approach), whereas substrates 138 and 139 are used in the modular (stepwise) approach, which uses bifunctional building blocks with temporarily masked functionalities that can be orthogonally activated to perform CuAAC reactions. At one end, the alkyne can be masked as a TMSalkyne or activated as a free terminal alkyne, whereas at the other end, the azide is activated as such or masked as an epoxide (that can be opened by an azide ion).…”

From Sweet Molecular Giants to Square Sugars and Vice Versa

“…Very recently, Seoane and Daher reported a related lego strategy for the synthesis of cyclodextrin analogues based on carbasugar building blocks. 92 At one end, the CuAAC reactive terminal alkyne is masked as a TMS-alkyne, whereas at the other end, the azide is masked as an epoxide ( OFF ) and is unmasked by way of azide anion ring opening. One advantage of CuAAC in the context of click chemistry and bioconjugation is the formation of a stable and non-toxic triazole ring.…”