Stereospecific Synthesis of C₂ Symmetric Diamines from the Mother Diamine by Resonance-Assisted Hydrogen-Bond Directed Diaza-Cope Rearrangement

Abstract

Sixteen diphenylethylenediamine analogues including those with electron donating, electron withdrawing, and sterically bulky substituents have been prepared in good overall yields (70-90%) and in enantiomerically pure form (>99% ee) by diaza-Cope rearrangement reaction. A single chiral mother diamine, ((R,R)-1,2-bis-(2-hydroxyphenyl)-1,2-diaminoethane), is reacted with appropriate aldehydes to form the initial diimines that rearrange to give all the product diimines in the (S,S) form. The daughter diamines are obtained by hydrolysis of the product diimines. Density functional theory computation shows that resonance-assisted hydrogen-bond is the main driving force behind all the rearrangement reactions. Chiral high performance liquid chromatography and circular dichroism spectroscopy show that the highly stereospecific rearrangement reactions take place with apparent inversion of stereochemistry.

Dynamic Kinetic Resolution of α-Keto Esters via Asymmetric Transfer Hydrogenation

“…The development of the “mother diamine”/diaza-Cope approach to the synthesis of C 2 -symmetric 1,2-diamines 10 allowed facile screening of a number of chiral diamine backbones. We found that the α-naphthyl/triisopropylbenzenesulfonamide ligand L7 considerably increased the selectivity (88:12 er, entry 7).…”

Asymmetric Synthesis of Diverse Glycolic Acid Scaffolds via Dynamic Kinetic Resolution of α-Keto Esters

“…Utilizing the “mother diamine”/diaza-Cope approach to the synthesis of C 2 -symmetric 1,2-diamines, 19 screening of a number of chiral diamine backbones was conducted. The α-naphthyl/triisopropylbenzenesulfonamide ligand L8 considerably increased the selectivity (88:12 er, Table 2).…”

Natural polarity inverted

“…reactions of carbonyl-containing compounds, and behave as carbon nucleophiles. Several non-enantioselective transformations have previously been reported [10][11][12][13] , and the sole example of a highly enantioselective carbon-carbon (C-C) bond-forming reaction with 2-azaallyl anions was a palladiumcatalysed coupling with carbon electrophiles 14 .…”