Details

Autor(en) / Beteiligte

• Kundrat, Ondrej
• Dvorakova, Hana
• Böhm, Stanislav
• Eigner, Vaclav
• Lhotak, Pavel

Titel

S-Alkylation of Thiacalixarenes: How the Regio- and Stereoselectivities Depend on the Starting Conformation

Ist Teil von

• Journal of organic chemistry, 2012-03, Vol.77 (5), p.2272-2278

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2012

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• S-alkylation of all four thiacalix[4]arene conformations was accomplished using alkyl triflates. The corresponding sulfonium salts are formed in a highly regio- and stereoselective manner depending on the conformation used. Interestingly, only mono- or disubstituted sulfonium salts can be prepared. Although many regio- and stereoisomers are theoretically possible, only one dialkylated cone and 1,2-alternate derivatives were formed, while only a single isomer of monoalkylated partial cone and 1,3-alternate were isolated. The combination of experimental results with the quantum-chemical approach using the B3LYP/6-311G(d,p) method resulted in the elucidation of the rules governing the regio- and stereochemical outcomes of the alkylation reactions. All S-alkylated compounds represent a novel type of substitution pattern in calixarene chemistry showing the wide-ranging possibility of thiacalixarene skeleton modifications.