Organocatalytic asymmetric sulfa-Michael addition of thiols to α,β-unsaturated hexafluoroisopropyl esters: expeditious access to (R)-thiazesim.

A highly efficient organocatalytic asymmetric SMA reaction of hexafluoroisopropyl α,β-unsaturated esters has been developed. Introducing electron-withdrawing hexafluoroisopropyl ester is crucial to enhancing the electrophilicity of unsaturated esters as SMA acceptors. The catalytic system performs well over a broad scope of α,β-unsaturated esters and diversified thiols and provides facile access to (R)-thiazesim in a one-pot protocol.