A Novel Counterion Effect on the Diastereoselectivity in the MnIII(salen)-Catalyzed Epoxidation of Phenyl-Substituted cis-Alkenes

✍ Scribed by Waldemar Adam; Konrad J. Roschmann; Chantu R. Saha-Möller

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 228 KB
• Volume: 2000
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/1099-0690(200011)2000:21<3519::aid-ejoc3519>3.0.co;2-f

✦ Synopsis

The catalytic oxidation of the phenyl-substituted cis alkenes 1a,b by the Mn III (salen)X complexes 3a-f with iodosyl benzene (PhIO) as oxygen source affords the corresponding epoxides 2a,b in cis/trans ratios of 79:21 to 26:74. The diastereoselectivity (cis/trans ratio) depends on the counterion of the Mn III (salen)X complexes 3a-f. Thus, for the complexes 3a-c (Cl -, Br -and AcO -as ligating counterions) extensive iso- [a]