title: A highly efficient asymmetric organocatalytic aldol reaction in a ball mill.
abstract: Anti-aldol products with up to >99 % enantiomeric excess (ee) have been obtained by proline catalysis in excellent yields under experimentally simple solvent-free conditions. Efficient mixing of all the components is accomplished by applying a mechanochemical technique (ball milling). The catalysis is air and moisture tolerant and can be performed with non-purified starting materials. Even mixtures of solely solid compounds react, giving (mostly solid) products through a partially homogeneous (honey-like) intermediate melt. Since the reactant ratio is almost 1:1 (avoiding the common excess of ketone), the product isolation is easy leading to high aldol product yields.
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany.
authors.forename: Belén
authors.initials: B
authors.lastname: Rodríguez
authors.forename: Angelika
authors.initials: A
authors.lastname: Bruckmann
authors.forename: Carsten
authors.initials: C
authors.lastname: Bolm