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A Highly Efficient Asymmetric Organocatalytic Aldol Reaction in a Ball Mill
Author(s) -
Rodríguez Belén,
Bruckmann Angelika,
Bolm Carsten
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200700188
Subject(s) - aldol reaction , ball mill , catalysis , enantiomeric excess , chemistry , homogeneous , ketone , solvent , organic chemistry , chemical engineering , materials science , enantioselective synthesis , thermodynamics , engineering , physics
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.