Fig. 4: The tungsten-promoted double-protonation of anisole followed by electrophilic aromatic substitution (EAS), reduction, and addition of cyanide ion.

HOTf = CF3SO3H; Tp = trispyrazolylborate. 6,9,15,18: Ar = 4-methoxyphenyl; 7,10,16,19: Ar = 4-hydroxyphenyl; 8,11,17,20: Ar = thiophen-2-yl. Yields for 9–11: 50–70%.