Multi-channel transformations of 1,3-diarylpropynones under superelectrophilic activation conditions: concurrence of intra- and intermolecular reactions. Experimental and theoretical study

1,3-Diarypropynones undergo concurrent multi-channel transformations in Bronsted (FSO3H, TfOH) and Bronsted–Lewis (HF–SbF5, TfOH-SbF5) superacids, leading intramolecularly to 3-arylindenones, or intermolecularly to 1,3,3-triarylpropenones, and dimeric structures. The outcome depends on the electronic donor-acceptor properties of the substituents in the aromatic rings of the 1,3-diarylpropynones, and on the added aromatic external π-nucleophiles. The orbital energies, atom charges, orbital contributions, and global electrophilicity indices of the cationic intermediates have been calculated by DFT methods to explain these transformations.

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