Herein, we described an efficient method for the construction of highly functionalized diazirines from the carbohydrazide and diazo-substituted hypervalent iodine reagents. Unambiguous transformation has been designed with user applicable and easy practicable conditions. Remarkably, D-glucose, menthol, aspirin, proline, and lithocholic acid were efficiently diazirinated. Furthermore, the method is mild, robust, and highly selective, which successfully converted a variety of aryl, alkyl, benzyl, and heterocyclic hydrazides into the corresponding diazirine derivatives.

A chemoselective route to thiazolines and thiazines has been devised by heterocyclization of viable α-N-hydroxyimino-β-oxodithioesters with 2-chloroethylamine hydrochloride/3-chloropropylamine hydrochloride, which does not require metals or additives and proceeds at 0-60 °C. The overall transformation involves base mediated intramolecular cyclization of α-N-hydroxyimino-β-oxodithioesters to 4-membered oxazete-4-thione intermediates followed by coupling with chloroalkyl amines via tandem ring cleavage and CÀ N/CÀ S bonds formation enabling the construction of thiazolines/thiazines in one-pot. This strategy allows broadening the arsenal of synthetic methods to obtain N,S-heterocycles utilizing substrates prepared according to reported procedures.

No abstract

No abstract

A facile and efficient one-pot synthesis of bench-stable quinoxaline N-oxides has been realized using α-oxoketene N,S-acetals and tert-butyl nitrite (TBN) in open air via cascade annulation. The double functionalization of N,S-acetals proceeds through an unanticipated (Csp2)-H nitrosation by NO radical (generated in situ by TBN) and subsequent intramolecular N-arylation leading to quinoxaline, which undergoes oxidation to quinoxaline N-oxides harboring three variegated substituents on their framework. Notably, two new CN bonds are formed with the same N-oxide nitrogen. This protocol features short reaction time, good functional group tolerance and mild conditions without the use of catalyst and external additive.