The possible reaction models for these three reactions were investigated. For the asymmetric arylation of amino acid ester 1a with 2a, once the reactant 2-nitro fluorobenzene 2a was replaced by 3-nitro fluorobenzene or 4-nitro fluorobenzene, the reaction efficiency was greatly decreased. Protecting the 2' hydroxyl of the chiral aldehyde catalyst CA-1 also prevented the formation of product 3a with high efficiency (Figure ). These results indicated that hydrogen bond interactions may have occurred between the 2' hydroxyl of CA-1 and the nitro group of 2-nitro fluorobenzene 2a. Thus, a possible transition state I (TS I) was proposed for the production of (S)-3a.