Triflic-Acid-Mediated Polycondensation of Carbonyl Compounds with Aromatic Hydrocarbons – A Theoretical Study

✍ Scribed by Alfredo López Lira; Mikhail G. Zolotukhin; Lioudmila Fomina; Sergei Fomine

• Book ID: 102495219
• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 238 KB
• Volume: 16
• Category: Article
• ISSN: 1022-1344
• DOI: 10.1002/mats.200600084

✦ Synopsis

Abstract

Mono‐ and diprotonated reaction intermediates involved in the acid‐catalyzed polyhydroxyalkylation of aldehydes and ketones of the general formula R~1~COR~2,~ (R~1~ = H, CH~3~, CF~3~ and R~2~ = Ph, CH~3~, CF~3~) with benzene and biphenyl, were studied theoretically at PBE0/aug‐cc‐PVTZ//PBE0/6‐31 + G** level of theory. The calculations performed for sulfuric acid and TFSA‐catalyzed reactions showed that for all studied reactions the enhancement of the reactivity of diprotonated species is not sufficient to compensate for the large positive Gibbs energy of second protonation. An alternative mechanism has been proposed for the reaction between benzene and benzaldehyde in TFSA involving only monoprotonated species. The low reactivity of carbonyl compounds with electron donating substituents is due to excessive stabilization of monoprotonated species rendering the reaction thermodynamically impossible.

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