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Investigation of the Influence of pH on the Catalytic Asymmetric Hydrogenation in Aqueous Micellar Media
Author(s) -
Grassert Ingrid,
Kovács József,
Fuhrmann Hans,
Oehme Günther
Publication year - 2002
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/1615-4169(200206)344:3/4<312::aid-adsc312>3.0.co;2-j
Subject(s) - chemistry , cationic polymerization , amphiphile , aqueous solution , asymmetric hydrogenation , micelle , catalysis , aqueous medium , micellar solutions , ionic strength , organic chemistry , inorganic chemistry , enantioselective synthesis , copolymer , polymer
The influence of pH on the asymmetric hydrogenation of α‐amino acid precursors was investigated in the presence of different types of amphiphiles in water as medium. Non‐ionic, cationic and zwitterionic amphiphiles gave optimal results with respect to activity and enantioselectivity between pH 2 and pH 5. Anionic amphiphiles were effective in the range from pH 2 up to pH 8 (sometimes pH 9). Comparable results were obtained with cationic and anionic polymeric micelles. Some relationships exist between CH/CD exchange in D 2 O and the pH dependence of the hydrogenation. As a practical consequence the pH in micellar hydrogenation systems should be chosen between pH 2 and pH 4.