Bis(2-alkylpyrrolidin-1-yl)methylidenes as Chiral Acyclic Diaminocarbene Ligands

2-Alkylpyrrolidines were used as building blocks for acyclic diaminocarbenes (ADCs). First, ureas were made from the corresponding amines, and then the urns were converted to chloro-amidiniums. The chloroamidiniums served as direct precursors to ADCs, and palladium complexes were made utilizing oxidative addition, whereas lithium halogen exchange was performed to generate rhodium complexes. The carbene ligands were characterized through use of NMR, mass spectrometry, and X-ray analysis, and from X-ray structures, steric parameters were calculated as % V-Bur values. The ability of these ligands to direct stereochemistry and enhance activity was explored in the Suzuki cross-coupling reaction and the 1,2 addition of arylboronic acids to aldehydes.