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

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)

Self condensation of enamines mediated by acetylation. A novel approach to 1-(azol-5-yl)-(1E,3Z)-butadiene-4-N,N-dimethylamines

Novel self-condensation of 3-(azol-5-yl)-1,1-dimethylenamines has been found to form new C-C bonds leading to 2,4-(1,2,3-triazole-1,2,3-thiadiazole-3- phenylisothiazole)-(1E,3Z)-5-yl-butadiene-1-amines. The discovered reaction represents a new example of C-H functionalization in unsaturated systems and can serve an efficient synthetic approach to rational design of new 2,4-(diazole-5-yl)-dieneamines. © 2012 The Royal Society of Chemistry