Enantioenriched 1,1-diaryl ethanes, which are recognized as valuable units in active pharmaceutical ingredients (API), are challenging structural motifs to access. We hypothesized that this newly developed asymmetric hydroarylation strategy could facilitate access to enantioenriched 1,1-diaryl ethanes and allow for a rapid buildup of molecular complexity. As outlined in Scheme 5, an initial screen of several chiral NHCs that showed activity in the above studies revealed that ortho-substitution on the N,N-diaryl imidazolium scaffold had a large effect on reactivity and enantioselectivity. Though L5•HBF4 exhibited poor regioselectivity control (linear to branched), steric effects were important in the observed enantioselectivities. Changing the identity of the aryl groups on imidazolium in L7•HBF4 improved regioselectivity, though enantioselectivity was diminished. Further decreasing the steric hinderance with monosubstituted N,N-diaryl imidazolium L8•HCl suppressed the formation of linear product while increased the yield of the branched product, albeit with negligible improvements in enantioselectivity. As modification of the mono-substituted arene of the imidazolium did not give improved results (L9•HCl), we opted to explore the preliminary scope of this reaction with L8•HCl, which gave the best reactivity and regioselectivity. 1,1-diaryl product 4ab was formed in 80% yield and 66:34 e.r. when reacting benzoxazole (1a) with styrene (2b). This method could be applied to 1-and 2-vinyl naphthalenes (2d, 2c), accessing exclusively the branched product with moderate control of enantioselectivity. More sterically hindered 2,4,6-trimethyl styrene (2e) did not undergo the hydroarylation reaction presumably due to the repulsion between substrate and the NHC ligand. While the combination of regioselectivity and enantioselectivity of hydroarylations of simple styrenes falls short of the levels needed for synthetic application in its current form, the insights provided into the role of NHC structure in modulating the reaction outcome will be useful in guiding further study. Scheme 5. Asymmetric alkylation with styrene and its derivatives. Reactions were performed at 0.10 mmol scale and yields were reported for isolated products.