Synthesis of novel carbo- and heteropolycycles. 12. A new versatile synthesis of oxazoles by intramolecular aza-Wittig reaction

Polymer‐Supported Hypervalent Iodine Reagent Mediated Synthesis of α‐Azidoketones

“…The solvent was evaporated off and the residue was purified by chromatography on a silica gel column eluting with AcOEt-n-hexane (1:3) to give 140 mg (87%) of 3a. Oily compound (lit., 5 …”

“…4 The synthesis of a-azidoketones can be commonly achieved by azido-halogen exchange reactions of a-haloketones. 5 In addition, a-azidoketones have been successfully prepared from reaction of sodium azide with a-tosyloxyketones by treatment with surfactant pillared clays 6 and triphase catalysis under ultrasound irradiation 7 in organic solvents such as chloroform or acetonitrile. Hypervalent iodine(III) reagents have received continuous attention due to their versatile utility in organic synthesis, ready availability, and relatively non-toxic properties.…”

Five‐Membered Heterocycles: 1,3‐Azoles

“…Oxazoles can also be prepared from b-(acyloxy)vinyl azides by reaction with phosphorous(III) reagents (Table 10. This route is particularly useful for the synthesis of acid-labile oxazole derivatives (Table 10.5) [93].…”

Eight‐Step Synthesis of Routiennocin

“…Subsequent treatment of the resulting ester with PA C H T U N G T R E N N U N G (OEt) 3 in THF triggered the intramolecular Staudinger reaction to give benzoxazole 6 (70% yield, 2 steps). [29] Scheme 1. Retrosynthetic analysis of routiennocin (1).…”