Enantioselective epoxidation of olefins catalyzed by two novel chiral poly-salen–Mn(III) complexes

✍ Scribed by Xiaoquan Yao; Huilin Chen; Weiran Lü; Guizhi Pan; Xinquan Hu; Zhuo Zheng

• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 62 KB
• Volume: 41
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)01843-8

✦ Synopsis

Two novel chiral poly-salen-Mn(III) complexes 1 and 2, derived from (R,R)-1,2-diaminocyclohexane and the disalicylaldehydes 5 and 6 were synthesized and employed in the enantioselective epoxidation of olefins. A range of 30-92% ee and 75-97% yield was achieved in NaClO/4-PPNO and m-CPBA/NMO oxidant systems when substituted styrenes and substituted 2,2-dimethylchromenes were used as substrates. Furthermore, the poly-salen-Mn(III) complexes could be recovered easily and recycled efficiently several times by a simple catalysis/separation method. After five reactions, an 82% ee and 78% yield of epoxide were obtained using 2,2-dimethylchromene as substrate.