Front Cover: Stereospecific Synthesis of Fluorinated Pyrazolidinones and Isoxazolidines via a Catalyst‐Free 1,3‐Dipolar Cycloaddition of β‐Fluoroalkylated α,β‐Unsaturated 2‐Pyridylsulfones (Asian J. Org. Chem. 9/2018)

Abstract

The regio‐ and stereoselective 1,3‐dipolar reaction is an important tool to build five‐membered heterocycles. Fluoroalkylated α,β‐unsaturated building blocks were used in the 1,3‐dipolar reaction of nitrones and azomethine imines without any catalysts and additives to obtain fluorinated pyrazolidinones and isoxazolidines. High endo‐selectivity for nitrones and exo‐selectivity for azomethine imines were observed, and supported by DFT calculations of Gibbs free energy changes in CH3CN. More information can be found in the Full Paper by Yi‐Yong Huang et al. on page 1830 in Issue 9, 2018 (DOI: 10.1002/ajoc.201800435).