1,2‐Benzothiazine Derivatives from Sulfonimidamides by Metal‐Catalyzed Annulation Reactions in Solution and under Solvent‐Free Mechanochemical Conditions
Jan‐Hendrik Schöbel, Philipp Elbers, Khai‐Nghi Truong, Kari Rissanen, Carsten Bolm
Abstract
Abstract Three‐dimensional aza‐analogues of 1,2‐benzothiazine 1,1‐dioxides have been prepared from sulfonimidamides. Two different protocols are presented. The first is a rhodium‐catalyzed annulation reaction with α ‐sulfonyloxyketones leading to 4‐unsubstituted benzothiazine derivatives. By selective bromination with NBS the heterocyclic ring can further be functionalized. In the second approach, an iridium catalyst is applied under solvent‐free mechanochemical conditions providing products with 3,4‐disubstituted thiazine rings from diazoketo esters and diazoketo sulfones. magnified image
Topics & Concepts
BenzothiazineChemistryAnnulationCatalysisHalogenationIridiumRhodiumSolventThiazineOrganic chemistryRing (chemistry)Combinatorial chemistrySynthesis and Catalytic ReactionsCatalytic C–H Functionalization MethodsPhenothiazines and Benzothiazines Synthesis and Activities