Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Published in: Beilstein journal of organic chemistry Vol. 13; no. 1; pp. 2569 - 2576
• Main Authors: Medvedev, Jury J, Efimov, Ilya V, Shafran, Yuri M, Suslonov, Vitaliy V, Bakulev, Vasiliy A, Nikolaev, Valerij A
• Format: Journal Article
• Language: English
• Published: Germany Beilstein-Institut zur Föerderung der Chemischen Wissenschaften 30.11.2017; Beilstein-Institut
• Subjects: [4 + 1]-annulation; catalysis; Chemistry; diazo compounds; domino reactions; Full Research Paper; Hydrocarbons; thiophenes; [4 + 1]-annulation; catalysis; thiophenes; diazo compounds; domino reactions
• ISSN: 1860-5397; 2195-951X; 1860-5397
• DOI: 10.3762/bjoc.13.253

A new approach towards the synthesis of multisubstituted thiophenes is elaborated based on Rh(II)-catalyzed domino reactions of acyclic diazoesters with α-cyanothioacetamides. It provides a way for the preparation of 5-amino-3-(alkoxycarbonylamino)thiophene-2-carboxylates, 2-(5-amino-2-methoxycarbonylthiophene-3-yl)aminomalonates and (2-cyano-5-aminothiophene-3-yl)carbamates with the preparative yields of up to 67%. It was also shown that α-cyanothioacetamides easily interact with dirhodium carboxylates to give rather stable 2:1 complexes, resulting in an evident decrease in the efficiency of the catalytic process at moderate temperatures (20-30 °C).