We find that a bulky pyridine-based catalyst promotes carbonate-forming reactions that ratchet the displacement of the macrocycle away from the reactive sites on the track. Under reaction conditions where both attachment and cleavage of the Fmoc groups occur through different processes, and the cleavage reaction occurs at a rate independent of macrocycle location, net directional rotation of the molecular motor continues for as long as unreacted fuel remains. We anticipate that autonomous chemically-fuelled molecular motors will find application as engines for molecular nanotechnology. 2, 19,20

Catalysis with chiral secondary amines (asymmetric aminocatalysis) has become a well-established and powerful synthetic tool for the chemo- and enantioselective functionalization of carbonyl compounds. In the last eight years alone, this field has grown at such an extraordinary pace that it is now recognized as an independent area of synthetic chemistry, where the goal is the preparation of any chiral molecule in an efficient, rapid, and stereoselective manner. This has been made possible by the impressive level of scientific competition and high quality research generated in this area. This Review describes this "Asymmetric Aminocatalysis Gold Rush" and charts the milestones in its development. As in all areas of science, progress depends on human effort.

Switch it on! The activity of an organocatalytic group incorporated within a rotaxane architecture can be controlled by switching the position of the macrocycle. The system was used to mediate the progress of the Michael addition of an aliphatic thiol to trans‐cinnamaldehyde.

Optically active 2,5-disubstituted-cyclohexen-2-one derivatives have been prepared in a one-pot process consisting of five reaction steps: an organocatalytic asymmetric conjugated addition of beta-ketoesters to alpha,beta-unsaturated aldehydes that proceeds in aqueous solutions or under solvent-free conditions has been implemented in a multi-step process.

[structure: see text]. The first general and highly enantioselective organocatalytic Friedel-Crafts alkylation of indoles with simple alpha,beta-unsaturated ketones has been accomplished. Central to these studies has been the identification of a new catalyst amine salt, in which both the cation and the anion are chiral, that exhibits high reactivity and selectivity for iminium ion catalysis.

Die Katalyse mit chiralen sekundären Aminen (asymmetrische Aminokatalyse) ist ein leistungsfähiges Verfahren zur chemo‐ und enantioselektiven Funktionalisierung von Carbonylverbindungen. Allein in den letzten acht Jahren wuchs dieses Feld zu einem eigenständigen Teilgebiet der Synthesechemie heran, dessen Ziel es sein muss, jede beliebige chirale Verbindung effizient, rasch und stereoselektiv herzustellen. Möglich wurde dieser Fortschritt durch hochqualifizierte Forschung und einen eindrucksvollen wissenschaftlichen Wettbewerb. Dieser Aufsatz beschreibt den “Goldrausch der asymmetrischen Aminokatalyse” und weist auf die Meilensteine dieser Entwicklung hin. Wie auf allen Wissenschaftsgebieten gilt letztlich: Der Fortschritt hängt vom Menschen ab.

We describe a three-compartment rotaxane information ratchet in which the macrocycle can be directionally transported in either direction along an achiral (disregarding isotopic labeling) track. Chiral DMAP-based catalysts promote a benzoylation reaction that ratchets the displacement of the macrocycle, transporting it predominantly to a particular end compartment determined by the handedness of the catalyst.

[reaction: see text] The first asymmetric aminolysis of trans-aromatic epoxides with anilines is described. The process affords enantioenriched anti-beta-amino alcohols in up to 99% ee. The complete regio- and diastereoselectivity observed uses commercially available [Cr(Salen)Cl] as a Lewis acid catalyst and in combination with a very simple experimental procedure renders the present reaction a facile and practical tool for the synthesis of chiral nonracemic anti-beta-amino alcohols.