Total synthesis of the taraxacine A natural product Ag(I)-catalysed imidate-alkyne cyclization.

A domino approach towards β-carboline natural product taraxacine A and its analogues was developed. The main step relies on a silver(I) and base co-catalysed imidate-alkyne cyclization. The reaction tolerates primary and secondary alcohols, and various substitutions in the indole are possible.