(N-Isocyanimino)triphenylphosphorane-Mediated, One-Pot, Efficient Synthesis of Sterically Congested 1,1,1-Trifluoro-2-(5-aryl-1,3,4-oxadiazol-2-yl)-2-propanol Derivatives via Intramolecular Aza-Wittig Reaction

Abstract

Reactions of (N-isocyanimino)triphenylphosphorane with 1,1,1-trifluoroacetone in the presence of aromatic (or heteroaromatic) carboxylic acids (3-methylbenzoic acid, 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, 2-furancarboxylic acid, and 2-thiophenecarboxylic acid) proceed smoothly at room temperature and in neutral conditions to afford sterically congested 1,1,1-trifluoro-2-(5-aryl-1,3,4-oxadiazol-2-yl)-2-propanol derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions, and no side reactions were observed.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Keywords:

• Aromatic carboxylic acid
• aza-Wittig reaction
• heteroaromatic carboxylic acid
• (N-isocyanimino)triphenylphosphorane
• 1,3,4-oxadiazole
• 1,1,1-trifluoroacetone

Acknowledgments

This research was supported by the Zanjan University and the Iran National Science Foundation (INSF).

Notes

^a We also used acetone and acetophenone instead of 1,1,1-trifluoroacetone 2 in this reaction, but no corresponding products 4 were observed.

^b Isolated yields.