Asymmetric Hydroboration of Diene Polymers

γ-Selective directed catalytic asymmetric hydroboration of 1,1-disubstituted alkenes.

Directed catalytic asymmetric hydroborations of 1,1-disubstituted alkenes afford γ-dioxaborato amides and esters in high enantiomeric purity (90-95% ee).

Oxygen-Directed Intramolecular Hydroboration

Metal-free homoallylic oxygen-directed intramolecular hydroboration is reported. Regioselectivities from 20:1 to 82:1 favoring the 1,3-dioxy-substituted products have been achieved using Me2S.BH3/TfOH followed by standard oxidative workup. Branching at the C5 position improves regioselectivity.

Two-stage optimization of a supramolecular catalyst for catalytic asymmetric hydroboration.

Systematic changes, first to the structure of the catalyst scaffold and then to the ligating groups, are used to fine tune supramolecular catalysts to achieve high regioselectivity (95-98%) and high enantioselectivity (94-97% ee) across a series of meta-substituted styrenes varying in electronic character.

Exploiting self-assembly for ligand-scaffold optimization: substrate-tailored ligands for efficient catalytic asymmetric hydroboration.

Magnesium-catalysed nitrile hydroboration

A b-diketiminato n-butylmagnesium complex is presented as a selective precatalyst for the reductive hydroboration of organic nitriles with pinacolborane (HBpin). Stoichiometric reactivity studies indicate that catalytic turnover ensues through the generation of magnesium aldimido, aldimidoborate and borylamido intermediates, which are formed in a sequence of intramolecular nitrile insertion and...