Organocatalytic Enantiodifferentiation of Two Aryl Groups with Similar Steric Hindrances: Construction of gem ‐Diaryl Acyclic Quaternary Stereocenters

Enantiodifferentiation of two aryl groups with similar steric hindrances is challenging. Although reactions involving diaryl ketones, diaryl alkenes, diaryl imines, diaryl carbenes, and diaryl radicals as substrates or intermediates have been reported for this purpose, successful enantiodifferentiation via diaryl conjugated carbanion intermediates has yet to be achieved. Moreover, existing methodologies predominantly rely on transition-metal catalysis and are largely limited to the construction of gem-diaryl tertiary stereocenters, with no examples reported for the construction of gem-diaryl acyclic quaternary stereocenters. In this study, we have developed a phase-transfer catalyst enabled enantiodifferentiation of two aryl groups with similar steric hindrances via diaryl conjugated carbanion intermediates. With this new approach, a variety of gem-diaryl compounds bearing acyclic all-carbon quaternary stereocenters were synthesized in high yields and excellent enantioselectivities.