Catalytic dearomative reduction of N-heteroarenes is of important transformations in organic synthesis as well as medicinal chemistry, since the reduced aza compounds such as dihydropyridines can be synthetic building blocks as well as structural motifs for bioactive natural products and pharmaceuticals. While hydrogenation and hydrosilylation are well-utilized methods for such dearomative reduction of N-heteroarenes, the dearomative hydroboration has recently emerged as a competent alternative with high selectivity and good functional group tolerance. This Minireview describes recent advances in the catalytic hydroboration of N-heteroarenes. A diverse range of new catalytic systems will be detailed with strong emphasis on their unique working modes, which are closely related to chemo-, regio- and stereooutcomes observed in the hydroboration of N-heteroarenes.
- catalytic reduction
- hydride transfer pathway