Chiral 1,4-bis-diphosphine ligands from optically active (Z)-olefines

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• 作者：Edoardo Cesarotti ; Isabella Rimoldi ; Paola Spalluto ; Francesco Demartin
• 关键词：Cyclizations ; Heterocycles ; Medium-sized rings ; Ring-closing metathesis ; Silyl enol ethers
• 刊名：Tetrahedron: Asymmetry
• 出版年：2007
• 出版时间：22 June 2007
• 年：2007
• 卷：18
• 期：11
• 页码：1278-1283
• 全文大小：281 K

文摘

The catalytic asymmetric hydrogenation of prochiral ketones was carried out with Ru(II) complexes prepared from new chiral diphosphine ligands, cis-(R,R)-2,5-bis[(diarylphosphino)]-3-hexenes. These new ligands were prepared from enantiomerically pure (R,R) or (S,S)-(Z)-3-hexene-2,5 diol and enantiomeric excesses up to 85 % were obtained in the reduction of 2-benzamidomethyl-3-oxobutanoate, starting material for the synthesis of 4-acetoxy-2-azetidinone.