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Need for a ligand to be enantiopure is questionable

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Hi, I believe there is a conceptual mistake on this page: I do not think that a chiral ligand needs to be enantiopure. Noyori introduced the concept of chiral amplification in asymmetric synthesis to describe the situation in which a ligand with a low ee induces a quite large ee in the product of the ligand-catalyszed reaction. This is one of the few but real cases of "non-linear effects" in asymmetric synthesis, the non-linearity indicating in this case that the ee of the product is not proportional to the ee of the ligand. His concept was developed on the basis of the DAIB-catalyzed addition of diorganozinc reagents on aldehydes, which is a typical case of ligand-accelerated catalysis. See Enantioselective Addition of Organometallic Reagents to Carbonyl Compounds: Chirality Transfer, Multiplication, and Amplification. R. Noyori and M. Kitamura, Angew. Chem., Int. Ed. Engl., 30, 49 (1991). I'm working on a new page on this topic, but would be interested on your feedback!

AlChimini (talk) 08:29, 26 May 2008 (UTC)[reply]

Possibly time for a rethink or a partial merge

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The opening sentences are tricky: "In chemistry a chiral ligand is a specially adapted ligand used for asymmetric synthesis. This ligand is an enantiopure organic compound which combines with a metal center by chelation to form an asymmetric catalyst ..."

  • "a chiral ligand is a specially adapted ligand" --> There is nothing special about chiral ligands - thousands of ligands are chiral.
  • "used for asymmetric synthesis" --> most chiral ligands are not used for asymmetric induction.
  • "is an enantiopure organic compound" --> no requirement for enantiopurity.
  • "combines with a metal center by chelation" --> the article is about chelation??

The article was initiated in a "prehistoric era" of Wiki-chem with the apparent intent of discussing asymmetric homogeneous catalysis. One possibility would be to move the contents to asymmetric catalysis and chiral auxiliary, where the focus is clearer. We could rename (move) parts of this article to "Privileged ligands". possibly start a section in diphosphines on chiral disphosphines.--Smokefoot (talk) 23:20, 13 October 2008 (UTC)[reply]

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