title: (Diisopinocampheyl)borane-mediated reductive aldol reactions of acrylate esters: enantioselective synthesis of anti-aldols.
abstract: The (diisopinocampheyl)borane promoted reductive aldol reaction of acrylate esters 4 is described. Isomerization of the kinetically formed Z(O)-enolborinate 5Z to the thermodynamic E(O)-enolborinate 5E via 1,3-boratropic shifts, followed by treatment with representative achiral aldehydes, leads to anti-α-methyl-β-hydroxy esters 9 or 10 with excellent diastereo- (up to ≥20:1 dr) and enantioselectivity (up to 87% ee). The results of double asymmetric reactions of 5E with several chiral aldehydes are also presented.
authors.affiliation: Department of Chemistry, Scripps Florida, Jupiter, Florida 33458, USA.
authors.forename: Christophe
authors.initials: C
authors.lastname: Allais
authors.forename: Philippe
authors.initials: P
authors.lastname: Nuhant
authors.forename: William R
authors.initials: WR
authors.lastname: Roush
mesh_terms: D000179:Acrylates / Q000138:chemical synthesis / Q000737:chemistry*; D000447:Aldehydes / Q000138:chemical synthesis / Q000737:chemistry*; D001880:Boranes / Q000737:chemistry*; D002384:Catalysis; D004952:Esters; D010084:Oxidation-Reduction; D013237:Stereoisomerism
chemical_list: C587231:(diisopinocampheyl)borane; D000179:Acrylates; D000447:Aldehydes; D001880:Boranes; D004952:Esters; C116609:3-hydroxybutanal; C036658:acrylic acid