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ChemFiles

OrganoCatalysts

 
ChemFilesTitle Vol . 2, 2002 Supplement
Grubbs' Catalysts & MacMillan's OrganoCatalysts™

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Grubbs' Catalysts / MacMillan's OrganoCatalysts™
Verkade's Superbases / Metal Catalysts and Ligands / References

MacMillan's OrganoCatalysts™

The vast majority of useful catalytic transformations involve inorganic or organometallic complexes as catalysts. Examples of catalysis by organic molecules can be found, but these examples are rare and have no general utility. OrganoCatalysis™ is a breakthrough technology, invented by Professor David MacMillan at Caltech, in which small organic molecules are designed and constructed to serve as general catalysts for asymmetric transformations of other substrates.

OrganoCatalysts™ have been successfully developed for several important reactions including the asymmetric variants of Friedel-Crafts alkylations,15 1,4 conjugate additions, Diels–Alder reactions,16 and 1,3 dipolar cycloadditions.17 These transformations enable an extremely broad range of chiral intermediates to be readily assembled (Scheme 8).


scheme8t

An interesting example employing RCM via Grubbs’ Catalyst in tandem with OrganoCatalysts™ is the three-step enantioselective synthesis of (-)-Ketorolac (Scheme 9). Ketorolac is currently manufactured in racemic form in a ten-step process. Studies of the pure (S)-enantiomer show enhanced biological activity and lower toxicity versus the racemic mixture.

OrganoCatalysts and OrganoCatalysis are trademarks of Materia, Inc.


scheme9
product4 product5
56,976-3

(5S)-2,2,3-Trimethyl-5-phenylmethyl-4-imidazolidinone monohydrochloride

2g
56,977-1

(2S,5S)-2-(1’,1’-Dimethylethyl)-3-methyl-5-
phenylmethyl-4-imidazolidinone

2g