ChemInform Abstract: Direct Carboxylation of Thiophenes and Benzothiophenes with the Aid of EtAlCl₂.

Abstract

Direct Carboxylation of Thiophenes and Benzothiophenes with the Aid of EtAlCl 2 . -The Lewis acid mediated carboxylation of thiophenes and benzothiophenes bearing alkyl or aryl substituents at the 2-or 3-positions affords the corresponding 2-or 3-carboxylic acids in up to 90% yield. Thiophenes having substituents at the 3-position show similar reactivities to those of 2-substituted regioisomers. The regioselectivity agrees with the ortho/para-directing nature of the substituents. -(NEMOTO*, K.; ONOZAWA, S.; KONNO, M.; MOROHASHI, N.; HATTORI, T.; Bull. Chem. Soc. Jpn. 85 (2012) 3, 369-371, http://dx.doi.org/10.1246/bcsj.20110335 ; Dep. Biomol. Eng., Grad. Sch. Eng., Tohoku Univ., Aoba, Sendai 980, Japan; Eng.) -H. Hoennerscheid 30-121