Electroreductive C-O bond activation in benzylic alcohols and their THF- and THP-acetal derivatives
2024 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
Student thesisAlternative title
Elektroreduktiv aktivering av C-O bindningar i bensyliska alkoholer och deras THF- och THP-acetalderivat (Norwegian)
Abstract [sv]
Detta projekt fokuserar på att studera bensylalkoholer, som påminner om ligninplattformsmolekyler, och rollen som deras respektive THF-acetalanaloger har, vilka bildas under silyleringsbetingelser under elektrokemiska förhållanden. Som en del av detta arbete syntetiserades THF-acetaler av utvalda alkoholer, jämsides med motsvarande THP-acetaler för jämförelse. Efter deras syntes testades acetalerna som startmaterial under elektrokemiska silyleringsbetingelser och utbyten och selektivitet jämfördes med de uppnådda när motsvarande alkoholer anänts. Det visade sig att silyleringsreaktionen är mycket substratberoende och att de elektroniska egenskaperna hos de funktionella grupperna placerade vid olika positioner av den aromatiska ringen spelar en viktig roll för produktbildning. Specifikt visade sig elektrondonerande grupper öka selektiviteten för den önskade produkten. Vidare resulterade de oskyddade alkoholerna i högre utbyten jämfört med deras respektive THF-/THP-acetalformer, vilket tyder på att acetalerna sannolikt inte är intermediärer i transformationen utan snarare utgör biprodukter.
Abstract [en]
The project at hand focuses on studying benzylic alcohols, reminiscent to lignin platform molecules, and the role of their respective THF-acetal analogues that form during silylation reactions under electrochemical conditions. As part of this work, THF-acetals of selected alcohols were synthesized. In addition, the corresponding THP-acetals were synthesized for comparison. Following their synthesis, the acetals were subjected to electrochemical silylation conditions developed in the Lundberg Lab and the yields and selectivities were compared to those of the corresponding alcohols. It was demonstrated that the silylation reaction is very substrate-dependent and that the electronic properties of the functional groups placed at different positions of the aromatic ring play an important role in the silylated product formation. Specifically, electron-donating groups were found to increase the selectivity for the desired product. Furthermore, the unprotected alcohols resulted in higher yields compared to their respective THF-/THP-acetal forms, suggesting that the acetals are unlikely to act as intermediates in the transformation but rather constituting side-products.
Place, publisher, year, edition, pages
2024.
Series
TRITA-CBH-GRU ; 2024:195
Keywords [en]
Electrosynthesis, electroreductive deoxygenation, organosilanes, lignin
Keywords [sv]
elektrosyntes, elektroreduktiv deoxygenering, organosilaner, lignin
National Category
Organic Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-352140OAI: oai:DiVA.org:kth-352140DiVA, id: diva2:1891148
Subject / course
Chemical Engineering
Educational program
Degree of Master - Chemical Engineering for Energy and Environment
Supervisors
Examiners
2025-02-202024-08-21