Waste as Catalyst: Tandem Wittig/Conjugate Reduction Sequence to α‐CF3 γ‐Keto Esters That Uses Ph3PO as Catalyst for the Chemoselective Conjugate Reduction

Reduce your waist: A highly efficient synthesis of α-CF3 γ-keto esters and trifluoromethylated 4,5-dihydro pyridazinones is reported based on tandem Wittig–conjugate reduction reactions, which directly utilize the Ph3PO waste from the Wittig reaction as the Lewis base catalyst to activate HSiCl3 for the chemoselective conjugate reduction.