Enantioselective Synthesis Of 3,3 '-Diaryl-Spinols: Rhodium-Catalyzed Asymmetric Arylation/Bf3-Promoted Spirocyclization Sequence

The enantioselective synthesis of a series of C-2-symmetric 3,3 '-diarylated 1,1 '-spirobiindane-7,7 '-diols (3,3 '-diaryl-SPINOLs) was developed by sequential Rh-catalyzed twofold asymmetric conjugate arylation/BF3-promoted diastereoselective spirocyclization (>20:1 d.r. and >99 % ee for all examples). Some phosphoramidite ligands were prepared from the 3,3 '-Ph-SPINOL and applied to several catalytic asymmetric reactions, and the 3,3 '-diarylated ligands showed higher enantioselectivities than the privileged nonsubstituted ligands.