Enantioselective alkylations of tributyltin enolates catalyzed by Cr(salen)Cl: access to enantiomerically enriched all-carbon quaternary centers.
The catalytic asymmetric alpha-alkylation of tributyltin enolates with a range of primary alkyl halides is catalyzed by a chiral Cr(salen) complex. The reaction constitutes the first transition-metal-catalyzed system for alpha-alkylation of carbonyl substrates with this important class of electrophiles, providing access to five-, six-, and seven-membered ring ketone products bearing alpha-quaternary stereocenters in high enantioselectivity and synthetically useful yields.
Doyle
Abigail G
AG
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Jacobsen
Eric N
EN
D000475:Alkenes / Q000737:chemistry*; D000478:Alkylation; D002384:Catalysis; D002857:Chromium / Q000737:chemistry*; D005029:Ethylenediamines / Q000737:chemistry*; D007659:Ketones / Q000138:chemical synthesis*; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D014220:Trialkyltin Compounds / Q000737:chemistry*
D000475:Alkenes; D005029:Ethylenediamines; D007659:Ketones; D009942:Organometallic Compounds; D014220:Trialkyltin Compounds; D002857:Chromium; C011559:tributyltin; C011452:disalicylaldehyde ethylenediamine