Organocatalytic Addition of Nitroalkanes to Aldehydes

The first catalytic asymmetric version of the Henry reaction with aldehydes was reported by Shibasaki in 1992 and was based on bifunctional multimetalHc 

Comprehensive Enantioselective Organocatalysis Catalysts, Reactions, and Applications, First Edition. 

Catalyst Solvent Time (h) Yield (%) Anti syn ee (%) Reference 

As shown in the Table 29.1, the screening of several chiral tetraaminophosphonium salts, in the test Henry reaction of nitromethane and benzaldehyde, showed that the aromatic substituent (Ar) on the diazaphosphacycle has a significant effect on catalyst efficiency. Thus, while catalyst 5 (Ar = Ph, 86% yield and 89% ee), and especially 6 (Ar = m-Xylyl, 36% yield and 45% ee), shown suboptimal performance, catalyst 7 (Ar = P-CF3-QH4) provides the corresponding final nitroaldol with 

Pitchumani and coworkers have found that per-6-amino-p-cyclodextrin (per-6-ABCD) catalyzes efficiently the Henry reaction in aqueous media [12], Thus, a series of aldehydes react with nitromethane or nitroethane to afford the corresponding P-nitroalcohol derivatives in excellent yields (88-99%) and selectivities (dr 15 1 and 79-99% ee) when using aromatic aldehydes, whereas aliphatic aldehydes afforded variable results (72-88% yield, 52-79% ee). 

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