Dynamic Control of Chiral Space in a Catalytic Asymmetric Reaction Using a Molecular Motor

• Published in: Science (American Association for the Advancement of Science) Vol. 331; no. 6023; pp. 1429 - 1432
• Main Authors: Wang, Jiaobing, Feringa, Ben L.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 18.03.2011; The American Association for the Advancement of Science
• Subjects: Alicyclic compounds; Alicyclic compounds, terpenoids, prostaglandins, steroids; Asymmetry; Catalysis; Catalysts; Catalysts: preparations and properties; Chemistry; Chirality; Conjugates; Enantiomers; enzymes; Exact sciences and technology; General and physical chemistry; Irradiation; Isomerization; Isomers; Molecular motors; Motor ability; Organic chemistry; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Preparations and properties; Reagents; Spectral index; Stators; Tasks; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Thiols; Transformations; Catalytic reaction; Configuration; Enzyme; Stepwise mechanism; Chiral compound; Molecular motor; Photochemical reaction; Rotor; Stereoselectivity; Racemic; Asymmetric synthesis; Enantiomer; Addition reaction; Chemical synthesis; Catalyst
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1199844

Enzymes and synthetic chiral catalysts have found widespread application to produce single enantiomers, but in situ switching of the chiral preference of a catalytic system is very difficult to achieve. Here, we report on a light-driven molecular motor with integrated catalytic functions in which the stepwise change in configuration during a 360° unidirectional rotary cycle governs the catalyst performance both with respect to activity and absolute stereocontrol in an asymmetric transformation. During one full rotary cycle, catalysts are formed that provide either racemic (R,S) or preferentially the R or the S enantiomer of the chiral product of a conjugate addition reaction. This catalytic system demonstrates how different molecular tasks can be performed in a sequential manner, with the sequence controlled by the directionality of a rotary cycle.