Stereodivergent and Enantioselective Access to Axial Chirality via Sequential Allylation/Peterson Elimination

While bifunctional allylation reagents have proven effective for constructing complex molecules bearing multiple central chirality, their potential for assembling axially chiral scaffolds remains undeveloped. Herein, we report a BINOL-catalyzed enantioselective allylation of prochiral carbonyl compounds using a type I bifunctional allylation reagent, which affords enantioenriched β-hydroxy silanes. The central chirality of these adducts is then efficiently transferred to axially chiral alkylidenecycloalkanes via an acid/base-controlled, enantiodivergent Peterson elimination. Moreover, this strategy is successfully extended to the enantioselective assembly of axially chiral diaryl ethers with three contiguous chiral elements. The dienyl motifs of the axial products provide a platform for further transformations. Density functional theory calculations are performed to elucidate the origin of the enantioselectivity.