Conjugate addition-enantioselective protonation to forge tertiary stereocentres ? to azaarenes via cooperative hydrogen atom transfer and chiral hydrogen-bonding catalysis

Conjugate addition–enantioselective protonation reactions

The addition of nucleophiles to electron-deficient alkenes represents one of the more general and commonly used strategies for the convergent assembly of more complex structures from simple precursors. In this review the addition of diverse protic and organometallic nucleophiles to electron-deficient alkenes followed by enantioselective protonation is summarized. Reactions are first categorized...

The enantioselective benzoin condensation promoted by chiral triazolium precatalysts: stereochemical control via hydrogen bonding.

The design of a new class of triazolium ion precatalysts incorporating protic substituents is described. These materials promote the enantioselective benzoin condensation of a range of aromatic aldehydes (1-62% ee). Catalyst evaluation studies strongly support the involvement of hydrogen bond donation by the catalyst in the stereocentre-forming step of the catalytic cycle.

Spin Transfer through Hydrogen Bonding

A polarised-neutron diffraction experiment on [Co(NH3)5(H20)][Cr(CN)6] shows the unexpected features of spin populat ions on the cobalt ((0.5(2) e) and the "ammine" hydrogen (0.8(1) e in total) atoms. A local density approximation DV-Xa calculation on a unit that models the molecular geometry in the crystal returns features that are broadly in agreement with the experiment. The calculation also...

Hydrogen bonding and alcohol effects in asymmetric hypervalent iodine catalysis: enantioselective oxidative dearomatization of phenols.

Cooperative hydrogen bonding in amyloid formation.

Amyloid diseases, including Alzheimer's and prion diseases, are each associated with unbranched protein fibrils. Each fibril is made of a particular protein, yet they share common properties. One such property is nucleation-dependent fibril growth. Monomers of amyloid-forming proteins can remain in dissolved form for long periods, before rapidly assembly into fibrils. The lag before growth has ...