Biaryl axes

Scheme 1) was required here, with excitation at 200 nm serving to afford 25 in a reproducible yield of 30 %. As expected, the reaction proceeded with complete atropselectivity for both the C16—CIS and C24—C26 biaryl axes, and the remaining material balance was mostly recovered starting material that could be recycled to enhance the overall throughput of material. As an aside, the final cyclization could also be accomplished under radical conditions by... 

The lactone concept also allowed easy access to monodentate phosphine ligands with sterically hindered biaryl axes, which catalysed the asymmetric hydrosilylation of styrenes in the presence of palladium (Scheme 5.49). ... 

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