Design of Chiral Phase-transfer Catalysts

In 1999, we designed and prepared structurally rigid, chiral spiro ammonium salts of type 14 derived from commercially available (S)- or (R)-l,l -bi-2-naphthol as a new C 2-symmetric chiral PTC and successfully applied them to the highly efficient, catalytic enantioselective alkylation of glycine Schiff base under mild phase-transfer conditions.  

Further study on the binaphthyl-based PTC led to the discovery that a chiral quaternary ammonium bromide (5)-16 possessing flexible straight-chain allqrl 

To fully induce the potential catalytic activity of binaphthyl-based PTCs such as we have developed binary phase-transfer catalysis using an 

Nonproteinogenic, chiral ot,ot-dialkyl-ot-amino acids possessing stereo-chemically stable quaternary carbon centres have been significant synthetic targets not only because they are often effective enzyme inhibitors but also they are indispensable for the elucidation of enzymatic mechanisms. Accordingly, numerous studies have been conducted to develop efficient methods for their preparation, and phase-transfer catalysis has made unique contributions.  

The binaphthyl-based PTC was also found to be an efficient catalyst for preparation of ot,ot-dialkyl-ot-amino acids by alkylation of Schiff bases of 

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