Magnesium , aqua species

The practicality of BINOL-Mg(ii) catalyst was further demonstrated by Ishihara et al. in a highly enantioselective addition of phosphorus nucleophiles 16 to a,p-unsaturated esters and ketones. Notably, by using water or BINOL as cocatalyst, a chiral cooperative Mg(ii) binaphtholate aqua complex was formed in the catalytic system that enabled the process to smoothly provide the corresponding adducts 17 and 18 in good to excellent yields and enantioselectivities. The authors supposed that the real active species was a cooperative 3 2 superamolecular complex of Hs-BINOLate/magnesium. Furthermore, the reaction could proceed by 1,4- or 1,2-addition by tuning the phosphorus nucleophile (Scheme 3.5). 

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