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Synthesis of Citronellal by Rh I ‐Catalysed Asymmetric Isomerization of N , N ‐Diethyl‐Substituted Geranyl‐ and Nerylamines or Geraniol and Nerol in the Presence of Chiral Diphosphino Ligands, under Homogeneous and Supported Conditions
Author(s) -
Chapuis Christian,
Barthe Michel,
de Saint Laumer JeanYves
Publication year - 2001
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20010131)84:1<230::aid-hlca230>3.0.co;2-v
Subject(s) - chemistry , citronellal , nerol , isomerization , ligand (biochemistry) , chiral ligand , geraniol , stereochemistry , selectivity , medicinal chemistry , enantioselective synthesis , organic chemistry , catalysis , chromatography , essential oil , biochemistry , receptor
For the asymmetric isomerization of geranyl‐ or neryldiethylamine (( E )‐ or ( Z )‐ 1 , resp.) and allyl alcohols geraniol or nerol (( E )‐ or ( Z )‐ 2 , resp.) to citronellal ( 4 ) in the presence of a [Rh I (ligand)cycloocta‐1,5‐diene)] + catalyst, the atropic ligands 5 – 11 are compared under homogeneous and polymer‐supported conditions with the non‐ C 2 ‐symmetrical diphosphino ferrocene ligands 12 – 16 . The t Bu‐josiphos ligand 13 or daniphos ligand 19 , available in both antipodal series, already catalyse the reaction of ( E )‐ 1 at 20° (97% e.e.) and favourably compare with the binap ligand 5 (see Table 1 ). Silica‐gel‐ or polymer‐supported diphosphino ligands usually afford similar selectivity as compared to the corresponding ligands applied under homogeneous conditions, but are generally less reactive. In this context, a polymer‐supported ligand of interest is the polymer‐anchored binap ( R )‐ 6 , in terms of reactivity, selectivity, and recoverability, with a turnover of more than 14400.