Reduktone von Tetron‐, Thiotetron‐ und Tetramsäuren, II. Reduktone durch Rhodium‐katalysierte Zersetzung von Diazoverbindungen

Abstract

Reductones of Tetronic, Thiotetronic and Tetramic Acids, II. – Reductones by Rhodium‐Catalyzed Decomposition of Diazo Compounds The diazoketones 2 have been synthesized by diazo transfer reaction with 2‐azido‐3‐ethylbenzthiazolium tetrafluoroborate. The rhodium‐catalyzed decomposition of compounds 2 in tert ‐butyl alcohol at 130°C furnishes the reductone monoethers 3 and after deprotection the aci ‐reductones 4 . Methylation of compounds 4 with diazomethane proceeds stepwise leading first to the monoethers 5 and then to the diethers 6 . The thiolactone 4b and even more the lactams 4c and 4d are stronger reducing agents than the lactone 4a . magnified image