Enantioselective Miyaura Reaction by Desymmetrizing C(sp2)-B Cross-Coupling of 1,1'-Biaryl-2,6-diyl Bis(nonaflates).

An efficient protocol for a desymmetrizing C(sp2)-B cross-coupling of achiral 1,1'-biaryl-2,6-diyl bis(nonaflates) and B-B reagents is disclosed. An in situ-formed palladium(0)-(S,S)-f-Binaphane complex discriminates between the enantiotopic nonaflate groups, and the subsequent transmetalation of the B-B reagent is enhanced by a copper co-catalyst. The enantiomeric excess of the chiral monoborylated product after reductive elimination is further improved by a downstream kinetic resolution, thereby converting the minor enantiomer into the corresponding achiral bisborylated biaryl byproduct. This enantioselective Miyaura reaction enables the synthesis of highly valuable, axially chiral boron compounds with superb enantiomeric ratios (up to e.r. = 99:1) and exhibits broad substrate scope and good functional-group tolerance.