Design and Synthesis of Rigid‐Featured Tertiary Amine‐Derived C2‐Symmetric Chiral Furan‐N,N′‐dioxide Ligands

To expand the chemical space of chiral N-oxides and chiral furan-containing ligands, herein we designed and synthesized a new class of rigid-featured tertiary amine-derived C-2-symmetric chiral furan-N,N'-dioxide (Fu-2NO) ligands from optically pure lprolinamides/hydroxylprolinamides in operationally simple two steps and up to 57% overall yield. The newly developed rigidfeatured chiral Fu-2NO ligands possesses two pyrroloimidazolone-based N-oxides as non-flat chiral walls, and afforded the opportunity for fine-tuning the ligand electronic and conformational properties by judicious choice of the substituent in the nonligating nitrogen atom. More importantly, The Fu-2NO ligands can tolerate air and moisture such that no special handling is needed for their storage, and can be applied in the Ni(II)-catalyzed asymmetric Friedel-Crafts alkylation reaction of indole.