title: 1,5-Stereoinduction in boron-mediated aldol reactions of β,δ-bisalkoxy methylketones containing cyclic protecting groups.
abstract: A study of the aldol reactions of boron enolates from methylketones that are protected with dimethylacetonide or di-tert-butylsilyl groups and that possess a trans or cis relationship between the chiral centers is presented. The main objective of this work was to evaluate the influence of the relative stereochemistry between the chiral centers and the steric and electronic influences of the cyclic protecting groups on the aldol reactions. The aldol adducts were obtained with moderate to high 1,5-anti stereoselectivity that was dependent on both the identity of the protecting group on the β,δ-oxygen stereocenters and the relative stereochemistry between the β and δ chiral centers. A theoretical analysis of the transition states involving these aldol reactions was performed utilizing DFT (density functional theory).
authors.affiliation: Chemistry Institute, State University of Campinas, UNICAMP, 13083-970, P.O. Box 6154, Campinas, SP, Brazil. ldias@iqm.unicamp.br
authors.forename: Luiz C
authors.initials: LC
authors.lastname: Dias
authors.forename: Ellen C
authors.initials: EC
authors.lastname: Polo
authors.forename: Marco A B
authors.initials: MA
authors.lastname: Ferreira
authors.forename: Cláudio F
authors.initials: CF
authors.lastname: Tormena