Recyclable Silica-Support Taniaphos/Copper(Ⅰ) complex for asymmetric allylic alkylation reactions

The first immobilization of recyclable Taniaphos/copper(Ⅰ) complex on a commercial accessible silica by thiol-ene coupling reaction has been achieved. The immobilization strategy and linker length are found to have significant impact on catalyst selectivities. Furthermore, we have realized the first heterogeneous asymmetric allylic alkylation reactions involving organometallic reagents using this catalyst system, and three types of cinnamyl bromide substrates are found to be suitable with up to 95% enantioselectivity and 96% yield. Notably, the catalyst shows good stability and cyclicity after five recycles without loss of selectivity and the products can be easily isolated with > 95% purity without chromatography purification.