N,N'-Dibenzyl-N,N'-ethylenetartramide: A Rationally Designed Chiral Auxiliary for the Allylboration Reaction

Article abstract of DOI:10.1021/ja00220a041

The chiral auxiliary designated in the title was designed as a probe of our previously suggested mechnism of asymmetric induction with tartrate allylboronates 1-3, namely that n/n electronic repulsive interactions between electron pairs on the aldehydic oxygen atom and an ester carbonyl disfavor transition-state C relative to A.The results reported for the new reagent 5 strongly support this thesis and suggest that the convergence of functional groups toward a metal center can be an exceedingly useful strategy for achieving a topological bias in the enantioselective functionalization of a carbonyl group.