Catalytic double hydroarylation of alkynes to 9,9-disubstituted 9,10-dihydroacridine derivatives by an electrophilic phenoxyphosphonium dication

The electrophilic pyridinium-substituted phenoxy-phosphonium dicationic salt [(PhO)P(2-(N-Mepy))Ph-2][B(C6F5)(4)](2), is shown to be an effective catalyst for the double hydroarylation of alkynes with diarylamines to afford a series of 9-methyl-9-aryl-9,10-dihydroacridine and 9,10-dimethyl-9-aryl-9,10-dihydroacridine derivatives.