Substrate scope of 9-BBN- and R3Sn-alkynes in [2 + 2 + 1] pyrrole synthesis.
Conc. = 0.2 M.
Conc. = 0.8 M.
Yield determined by NMR.
Selectivity with respect to all possible pyrrole products.
Other regioisomers cannot be quantified due to their low yield.