Abstract
The synthesis of multisubstituted pyrroles by the nickel-catalyzed reaction of N-tosyl alkynamides with arylboronic acids is reported. These reactions are triggered by alkyne arylnickelation, followed by cyclization of the resulting alkenylnickel species onto the amide. The reversible E/Z isomerization of the alkenylnickel species is critical for cyclization. This method was applied to the synthesis of pyrroles that are precursors to BODIPY derivatives and a biologically active compound.
Highlights
The synthesis of multisubstituted pyrroles by the nickel-catalyzed reaction of N-tosyl alkynamides with arylboronic acids is reported
The successful use of amides could provide a versatile synthesis of multisubstituted pyrroles, as shown in Scheme 1
Our investigations began with the reaction of alkynamide 1a with PhB(OH)[2] to give pyrrole 3aa, which was conducted in the presence of Ni(OAc)2·4H2O (10 mol%) in 2,2,2-trifluoroethanol (TFE) at 80 °C for 24 h (Table 1, entry 1)
Summary
The synthesis of multisubstituted pyrroles by the nickel-catalyzed reaction of N-tosyl alkynamides with arylboronic acids is reported. The successful use of amides could provide a versatile synthesis of multisubstituted pyrroles, as shown in Scheme 1. Our investigations began with the reaction of alkynamide 1a with PhB(OH)[2] to give pyrrole 3aa, which was conducted in the presence of Ni(OAc)2·4H2O (10 mol%) in 2,2,2-trifluoroethanol (TFE) at 80 °C for 24 h (Table 1, entry 1).
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