title: Highly stereoselective TiCl4-mediated aldol reactions from (S)-2-benzyloxy-3-pentanone.
abstract: Stereoselectivity of TiCl4-mediated aldol reactions from (S)-2-benzyloxy-3-pentanone is dramatically improved when the reaction is carried out in the presence of 1.1 equiv of tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME). The resultant 2,4-syn-4,5-syn adducts are then obtained in diastereomeric ratios up to 97:3, which proves that the appropriate choice of the Lewis acid (TiCl4-THF or DME vs Ti(i-PrO)Cl3) engaged in the process permits access to both syn-aldol adducts.
authors.affiliation: Departament de Química Orgànica, Universitat de Barcelona, Martí i Franqués 1-11, 08028 Barcelona, Catalonia, Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Rodríguez-Cisterna
authors.forename: Cristina
authors.initials: C
authors.lastname: Villar
authors.forename: Pedro
authors.initials: P
authors.lastname: Romea
authors.forename: Fèlix
authors.initials: F
authors.lastname: Urpí