The one-pot, selective cross pinacol-type couplings between two
structurally similar aromatic aldehydes promoted by low-valent titanium
generated unsymmetrical pinacols in moderate to good isolated yields
in an erythro/threo ratio
of up to 91:9. This synthetic methodology significantly extends
the scope of the cross pinacol-type couplings.
pinacol - pinacol-type coupling - cross coupling - McMurry coupling - low-valent titanium