1,1‐Bis(triflyl)alkadienes: Easy‐To‐Handle Building Blocks for Strongly Acidic Carbon Acids

Abstract 1,1‐Bis(triflyl)alkadienes are easily prepared by mixing bis(triflyl)methane and α,β‐unsaturated aldehydes and then used as easy‐to‐handle building blocks for the preparation of strongly acidic carbon acids. The reaction of these alkadienes with either NaBH4 or organocerium reagents gave the desired carbon acids through a β‐selective nucleophilic addition reaction. Similar reactions of a 1,1‐bis(trifyl)alkadiene with sterically bulky iPrMgBr resulted in a δ‐selective alkylation instead. The present β‐alkylation is the realization of the synthesis of β‐branched 1,1‐bis(triflyl)alkanes with an acidic CH moiety. Furthermore, when submitted to a Mukaiyama aldol reaction, such β‐branched carbon acids had a higher catalyst activity than that of the corresponding nonbranched carbon acids.