Nitroaldol proposed mechanism promoted

Figure 25. Proposed mechanism for the catalytic asymmetric nitroaldol reaction promoted by LLB, LLB-II, or LLB-Li-nitionate.

Shibasaki et al. have reported an asymmetric nitroaldol reaction catalyzed by chiral lanthanum alkoxide 18 to produce an optically active 2-hydroxy-1-nitroalkane with moderate-to-high enantiomeric excesses (Scheme 8B1.10) [27]. Apparently this novel catalyst acts as Lewis base. The proposed reaction mechanism is shown in Scheme 8B1.11, where the first step of the reaction is the ligand exchange between binaphthol and nitromethane. This reaction is probably the first successful example of the catalytic asymmetric reaction promoted by a Lew i s base metal catalyst. Future application of this methodology is quite promising. 

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