Editing Enantioselective synthesis (section)

===Enantioselective catalysis===
Enantioselective catalysis (known traditionally as "asymmetric catalysis") is performed using chiral [[catalysts]], which are typically chiral [[coordination complex]]es. Catalysis is effective for a broader range of transformations than any other method of enantioselective synthesis. The chiral metal catalysts are almost invariably rendered chiral by using [[chiral ligand]]s, but it is possible to generate chiral-at-metal complexes composed entirely of [[achiral]] ligands.<ref>{{cite journal|last=Bauer|first=Eike B.|title=Chiral-at-metal complexes and their catalytic applications in organic synthesis|journal=Chemical Society Reviews|year=2012|volume=41|issue=8|pages=3153–67|doi=10.1039/C2CS15234G|pmid=22306968}}</ref><ref>{{Cite journal|last1=Zhang|first1=Lilu|last2=Meggers|first2=Eric|date=2017-02-21|title=Steering Asymmetric Lewis Acid Catalysis Exclusively with Octahedral Metal-Centered Chirality|url=https://doi.org/10.1021/acs.accounts.6b00586|journal=Accounts of Chemical Research|volume=50|issue=2|pages=320–330|doi=10.1021/acs.accounts.6b00586|pmid=28128920|issn=0001-4842|url-access=subscription}}</ref><ref>{{Cite journal|last1=Huang|first1=Xiaoqiang|last2=Meggers|first2=Eric|date=2019-03-19|title=Asymmetric Photocatalysis with Bis-cyclometalated Rhodium Complexes|url=https://pubs.acs.org/doi/10.1021/acs.accounts.9b00028|journal=Accounts of Chemical Research|language=en|volume=52|issue=3|pages=833–847|doi=10.1021/acs.accounts.9b00028|pmid=30840435|s2cid=73503362 |issn=0001-4842|url-access=subscription}}</ref>
Most enantioselective catalysts are effective at low substrate/catalyst ratios.<ref>{{cite book|last1=N. Jacobsen|first1=Eric|last2=Pfaltz|first2=Andreas|last3=Yamamoto|first3=Hisashi|title=Comprehensive asymmetric catalysis 1-3|date=1999|publisher=Springer|location=Berlin|isbn=978-3-540-64337-1}}</ref><ref>{{cite journal |author1=M. Heitbaum |author2=F. Glorius |author3=I. Escher | title = Asymmetric Heterogeneous Catalysis | year = 2006 | journal = [[Angewandte Chemie International Edition]] | volume = 45 | issue = 29 | pages = 4732–4762 | doi = 10.1002/anie.200504212 | pmid = 16802397}}</ref> Given their high efficiencies, they are often suitable for industrial scale synthesis, even with expensive catalysts.<ref>Asymmetric Catalysis on Industrial Scale, (Blaser, Schmidt), Wiley-VCH, 2004.</ref> A versatile example of enantioselective synthesis is [[asymmetric hydrogenation]], which is used to reduce a wide variety of [[functional group]]s.

[[File:Noyori Asymmetric Hydrogenation Scheme.png|center|400px]]

The design of new catalysts is dominated by the development of new classes of [[ligand]]s. Certain ligands, often referred to as "[[privileged ligand]]s", are effective in a wide range of reactions; examples include [[BINOL]], [[Salen ligand|Salen]], and [[Bisoxazoline ligand|BOX]]. Most catalysts are effective for only one type of asymmetric reaction. For example, [[Noyori asymmetric hydrogenation]] with BINAP/Ru requires a β-ketone, although another catalyst, BINAP/diamine-Ru, widens the scope to α,β-[[alkenes]] and [[aromatic chemical]]s.