Cyclic β-diketones -- precursors of chiral 1,3-cyclohexadiene iron carbonyl complexes. Ligand exchange -- (−)-PPh₂(O-HC^*(Me)-COOEt) -- new, chiral, diastereomer-separ

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• 作者：Boh&aacute ; c ; Andrej ; Lettrichov&aacute ; Martina ; Hrnciar ; Pavel ; Hutta ; Milan
• 关键词：Cyclic β ; -diketones ; Iron tricarbonyl ; Ligand exchange ; Phosphine ; Phosphite ; Phosphinite ; Chiral ligand ; Chirality ; (S)-(&minus ; )-Ethyl lactate ; NMR spectroscopy ; CD spectra
• 刊名：Journal of Organometallic Chemistry
• 出版年：1996
• 出版时间：January 25, 1996
• 年：1996
• 卷：507
• 期：1-2
• 页码：23-29
• 全文大小：620 K

文摘

A synthesis of new, chiral tricarbonyliron complexes (1, 2) from 1,3-cyclohexanedione and 5,5-dimethyl-1,3-cyclohexanedione (dimedone) after their conversion to 1,3-diacetoxy-1,3-cyclohexadienes and complexation with Fe₂(CO)₉ is described. Ligand-exchange reactions of complexes 1,2 with PPh₃ (A), (−)-P(O-HC^*(Me)-COOEt)₃ ‘(−)-TEOCEOP’ (B) and (−)-PPh₂(O-HC^*(Me)-COOEt) ‘LACTODIPPHOS’ (C) were accomplished in good yield. A new prospective chiral ligand for organoiron chemistry, derived from commercially available (S)-(−)-ethyl lactate, (−)-PPh₂(O-HC^*(Me)-COOEt) (C) was found. By means of ligandC, a diastereoisomeric mixture of the (1,3-diacetoxy-1,3-cyclohexadiene)Fe(CO)₂PPh₂(O-HC^*(Me)-COOEt) complex 1C (1C¹²⁰ and 1C¹⁶⁰) was successfully separated.