Stereochemical diversity in chiral ligand design: discovery and optimization of catalysts for the enantioselective addition of allylic halides to aldehydes.
[reaction: see text] We have identified a new set of stereochemically diverse oxazoline ligands derived from simple amino acids that promote the Cr-catalyzed enantioselective addition of allylic halides to aldehydes in up to 95% ee. The Cr-catalyzed allylation using ligand 1d is rather insensitive to the nature of the allylic bromide (crotyl, allyl, and methallyl) in that >90% ee is observed for all three bromides evaluated in the addition to benzaldehyde.
Lee
Jae-Young
JY
Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-085, USA.
Miller
Jeremie J
JJ
Hamilton
Steven S
SS
Sigman
Matthew S
MS
D000447:Aldehydes / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry*; D002384:Catalysis; D002857:Chromium / Q000737:chemistry; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D010080:Oxazoles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D000447:Aldehydes; D000596:Amino Acids; D006846:Hydrocarbons, Halogenated; D010080:Oxazoles; D002857:Chromium