Application of Chiral Ferrocene Ligands in Asymmetric Palladium Catalyzed Allylic Substitution Reactions

doi:10.7523/j.issn.2095-6134.2004.3.021

Abstract

Abstract:

Thioether, selenide and phosphino derivatives of ferrocenyl oxazolines, synthesized from ferrocenyl oxazolines, were found to be effective in palladium catalyzed allylic alkylation with up to 99% ee. With P, N ligand, palladium catalyzed allylic amination was achieved with 97% ee. The enantio control was dominated by the central chirality. However, the match between planar chirality and central chirality is critical for high enantioselectivity. A series of planar chiral ferrocene modified bisphosphine pocket ligands were synthesized and found to be very effective in construction of quaternary carbon centers using asymmetric allylic alkylation. Some non coded alpha, alpha disubstituted amino acids were obtained with up to 75% ee using ketone imino esters. Using enolate of simple ketone as nucleophile, alpha, alpha disubstituted ketones were obtained with up to 95% ee. A new type of ferrocene based P, N ligands has been synthesized and was found to be very effective in regio and enantio selective palladium catalyzed allylic alkylation and amination of mono substituted allylic acetates. The free OH in the ligand was very important for selective control by the hydrogen bonding with benzylamine in later reaction, which was proved by experimental results.

Key words: asymmetric catalysis, ferrocene, planar chirality

CLC Number:

YOU ShuLi, HOU XueLong, DAI LiXin. Application of Chiral Ferrocene Ligands in Asymmetric Palladium Catalyzed Allylic Substitution Reactions[J]. , 2004, 21(3): 413-417.

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