Chiral salen-metal complexes as novel catalysts for asymmetric phase transfer alkylations

✍ Scribed by Yuri N. Belokon; Michael North; Vadim S. Kublitski; Nikolai S. Ikonnikov; Pavel E. Krasik; Viktor I. Maleev

• Publisher: Elsevier Science
• Year: 1999
• Tongue: French
• Weight: 242 KB
• Volume: 40
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(99)01214-9

✦ Synopsis

Chiral, salen-metal complexes have been tested as catalysts for the C-alkylation of aldimine Schiff's bases of alanine esters with alkyl bromides under phase-transfer conditions (solid sodium hydroxide, toluene, ambient temperature, 1-10% of the catalyst). The best catalyst, which was derived from a Cu(ID complex of (1R,2R or 1S,2S)-[N,N'-bis(2'-hydroxybenzylidene)]-l,2-diaminocyclohexane, gave ct-methyl-ct-amino acids with enantiomeric excesses of 70-96%.