Tuning the Basicity of a Metal-Templated Brønsted Base to Facilitate the Enantioselective Sulfa-Michael Addition of Aliphatic Thiols to α,β-Unsaturated<i>N</i>-Acylpyrazoles
The enantioselectiveaddition of aliphatic thiols to α,β-unsaturated N-acylpyrazoles catalyzed by a bis-cyclometalated iridium(III) complex with fine-tuned Bronsted basicity was investigated. Good to excellent yields (71–99 %) and enantioselectivities (86–98 % ee) were achieved at catalyst loadings of 0.2–2.5 mol-%. In this metal-templated catalyst design, the metal serves as a structural center and