A straightforward protocol to promote the tetrahydropyranylation of alcohols, using for the first time bioinspired acidic natural deep eutectic solvents (NADESs) as non-innocent reaction media under mild reaction conditions, was reported. This approach enables the preparation of several tetrahydropyranyl (THP) ethers starting from primary, secondary and tertiary alcohols in short reaction times and with high levels of chemoselectivity, working under air and without the need of additional catalyst. The sustainability of the methodology was further highlighted by its scalability and the easy recyclability of the NADES, allowing multigram preparations of THP ethers without any loss of the catalytic activity of the reaction media up to ten recycling steps. Telescoped, one-pot tetrahydropyranylation/nucleophilic acyl substitution transformations using the same eutectic mixture were also demonstrated.
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http://dx.doi.org/10.1002/cssc.202202066 | DOI Listing |
Org Lett
June 2024
Department of Organic Chemistry, Campus Miguel Delibes, University of Valladolid, 47011 Valladolid, Spain.
In this study, the use of terminal cyclopropylsilyl alcohols in Prins cyclization is reported as a very efficient methodology for the preparation of polysubstituted tetrahydropyrans, in which three new stereogenic centers have been created in a single pot. The reaction is general for a wide variety of aldehydes (alkylic, vinylic, aromatic, or dialdehydes), different types of alcohols, and halogenation agents providing high yields and excellent diastereoselectivity 2,3,4,6-tetrasubstituted tetrahydropyranyl frameworks. Interestingly, diastereomeric alcohols provide the same tetrahydropyranyl derivatives, showing that the reaction mechanism proceeds through common intermediates.
View Article and Find Full Text PDFJ Am Chem Soc
May 2024
Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea.
Hydrogels hold significant promise as drug delivery systems due to their distinct advantage of sustained localized drug release. However, the challenge of regulating the initial burst release while achieving precise control over degradation and drug-release kinetics persists. Herein, we present an ABA-type triblock copolymer-based hydrogel system with precisely programmable degradation and release kinetics.
View Article and Find Full Text PDFOrg Lett
February 2024
School of Chemistry, Joseph Black Building, University of Glasgow, University Avenue, Glasgow, G12 8QQ, U.K.
The I-K fragment (C31-C49) of the ciguatoxin CTX3C has been synthesized from a simple chiral pool derived tetrahydropyranyl alcohol. An efficient gold-catalyzed cyclization reaction of a γ'-hydroxy ynone has been used to accomplish efficient closure of ring K under mild conditions. The resulting vinylogous ester has been elaborated to give a complete tricyclic fragment bearing the dimethyl-substituted side chain required for assembly of the LM spirocyclic acetal portion of the target.
View Article and Find Full Text PDFChemSusChem
February 2023
Dipartimento di Chimica, Università degli Studi di Torino, Via Pietro Giuria 7, I-10125, Torino, Italy.
A straightforward protocol to promote the tetrahydropyranylation of alcohols, using for the first time bioinspired acidic natural deep eutectic solvents (NADESs) as non-innocent reaction media under mild reaction conditions, was reported. This approach enables the preparation of several tetrahydropyranyl (THP) ethers starting from primary, secondary and tertiary alcohols in short reaction times and with high levels of chemoselectivity, working under air and without the need of additional catalyst. The sustainability of the methodology was further highlighted by its scalability and the easy recyclability of the NADES, allowing multigram preparations of THP ethers without any loss of the catalytic activity of the reaction media up to ten recycling steps.
View Article and Find Full Text PDFMacromol Biosci
January 2023
Immunoassays-Immunosensors Lab, Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR "Demokritos", Aghia Paraskevi, 15341, Greece.
Surfaces for guided cell adhesion and growth are indispensable in several diagnostic and therapeutic applications. Towards this direction, four diblock copolymers comprising polyethylene glycol (PEG) and poly(2-tetrahydropyranyl methacrylate) (PTHPMA) are synthesized employing PEG macroinitiators of different chain lengths. The copolymer with a 5000 Da PEG block and a PEG-PTHPMA comonomers weight ratio of 43-57 provides a film with the highest stability in the culture medium and the strongest cell repellent properties.
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