Asymmetric catalysis of hetero-ene reactions with tridentate Schiff base chromium(III) complexes.
Tridentate Schiff base chromium(III) complex 1 catalyzes the asymmetric hetero-ene reaction between aryl aldehydes and either 2-methoxypropene or 2-trimethylsilyloxypropene to provide a series of beta-hydroxyenol ether products in high yields and enantioselectivities. X-ray crystallographic analysis of a closely related chromium complex reveals a bridged, dimeric structure bearing aquo-bound six-coordinate Cr(III) centers. A mechanism is proposed wherein water dissociation is effected by means of a chemical desiccant (BaO or silyl enol ether), thereby revealing the site for aldehyde complexation.
Ruck
Rebecca T
RT
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Jacobsen
Eric N
EN
D001547:Benzaldehydes / Q000737:chemistry; D001592:Benzyl Alcohols / Q000138:chemical synthesis*; D002384:Catalysis; D002857:Chromium / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004987:Ethers / Q000138:chemical synthesis*; D009942:Organometallic Compounds / Q000737:chemistry*; D012545:Schiff Bases / Q000737:chemistry*
D001547:Benzaldehydes; D001592:Benzyl Alcohols; D004987:Ethers; D009942:Organometallic Compounds; D012545:Schiff Bases; D002857:Chromium