Asymmetric reduction of aromatic ketones with chiral alkoxy-amineborane complexes

Industrial Methods for the Production of Optically Active Intermediates

“…An efficient catalyst based on a chiral modified borane pioneered by Itsuno and co-workers [148] has undergone considerable further development by Corey et al [149] Borane is used as an adduct with THF or dimethylsulfide as a stoichiometric reducing agent. The method has a broad scope and provides products with high ee values within short Scheme 64.…”

Reduction of Carbonyl Compounds with Chiral Oxazaborolidine Catalysts: A New Paradigm for Enantioselective Catalysis and a Powerful New Synthetic Method

“…After a survey of the extensive literature of these mixture reagents for hydride reduction and in an attempt to rationalize the basis for the observed enantioselectivities, we became very interested in a system introduced by Itsuno et al in 1981. [10] In this initial work, the authors reported the novel finding that mixtures of chiral amino alcohols such as (S)-valinol and BH 3´T HF in a ratio of 1:2 in THF at 30 8C effected the enantioselective reduction of a number of achiral ketones to chiral secondary alcohols in nearly 100 % yield with enantiomeric excesses in the range of 10 ± 73 % ee.…”

Exploring Structural Diversity in Ligand Design: The Aminoindanol Case

“…These species have proven to be an excellent option in the enantioselective reduction of ketones with borane for the production of enantioenriched secondary alcohols. The use of oxazaborolidines in asymmetric ketone reduction was introduced by Itsuno et al [36] although it was Corey who pro- posed the mechanism, which allowed for a rational development of the catalytic system. [37] Since their use was first described by Didiers group for the borane reduction of ketones, [38] the aminoindanol scaffold has been employed by other authors [18,39] in this reaction, either as the B À H, the B À Me or B À OMe derivative.…”