Photoredox activation and anion binding catalysis in the dual catalytic enantioselective synthesis of β-amino esters

Bergonzini, Giulia; Schindler, Corinna S.; Wallentin, Carl‐Johan; Jacobsen, Eric N.; Stephenson, Corey R. J.

doi:10.1039/c3sc52265b

Cited by 271 publications

(117 citation statements)

References 71 publications

Supporting

Mentioning

108

Contrasting

Unclassified

Order By: Relevance

“…[13] We subjected 8d to these oxidants, including ceric ammonium nitrate (CAN), periodic acid (H 5 IO 6 ), trichloroisocyanuric acid (TCCA), and CAN/Fe(bpy) 3 (PF 6 ) 2 [14] . Among the conditions examined, CAN in sulfuric acid gave the highest yield.…”

Section: Resultsmentioning

confidence: 99%

Intermolecular [3+2] Annulation of Cyclopropylanilines with Alkynes, Enynes, and Diynes via Visible Light Photocatalysis

2014

View full text Add to dashboard Cite

One-step synthesis of carbocycles substituted with amines from simple starting materials remains rare. We recently developed intermolecular [3+2] annulation of cyclopropylanilines with alkenes and alkynes that enable this one-step synthesis. Herein, we report our findings for a fullscale study of the annulation. Significant expansion of the substrate scope for both cyclopropylanilines and alkynes is achieved. A range of structurally diverse carbocycles substituted with amines is prepared.

show abstract

Section: Resultsmentioning

confidence: 99%

Intermolecular [3+2] Annulation of Cyclopropylanilines with Alkynes, Enynes, and Diynes via Visible Light Photocatalysis

2014

View full text Add to dashboard Cite

show abstract

“…In such dual-catalyst reactions, visible-light redox sensitizers are combined with asymmetric co-catalysts, such as chiral secondary amines [9][10][11][12][13] , chiral N-heterocyclic carbenes 14 , chiral Brønsted acids 15 , chiral Lewis acids 16 , or chiral thiourea 17 . With respect to single catalysts, ultraviolet light in combination with hydrogen bonding or Lewis acid interaction has been used previously in pioneering work to trigger enantioselective catalysis [18][19][20] , and an enantioselective cycloaddition induced by visible light-although not including photoinduced electron transfer-has been reported 21 ; also, an interesting but special case of photoactivated enamine catalysis was disclosed recently in which a transient electron donoracceptor complex is capable of absorbing visible light and triggering a charge transfer 22 .…”

mentioning

confidence: 99%

Asymmetric photoredox transition-metal catalysis activated by visible light

Huo

Shen

Wang

et al. 2014

Nature

561

265

View full text Add to dashboard Cite

Asymmetric catalysis is seen as one of the most economical strategies to satisfy the growing demand for enantiomerically pure small molecules in the fine chemical and pharmaceutical industries. And visible light has been recognized as an environmentally friendly and sustainable form of energy for triggering chemical transformations and catalytic chemical processes. For these reasons, visible-light-driven catalytic asymmetric chemistry is a subject of enormous current interest. Photoredox catalysis provides the opportunity to generate highly reactive radical ion intermediates with often unusual or unconventional reactivities under surprisingly mild reaction conditions. In such systems, photoactivated sensitizers initiate a single electron transfer from (or to) a closed-shell organic molecule to produce radical cations or radical anions whose reactivities are then exploited for interesting or unusual chemical transformations. However, the high reactivity of photoexcited substrates, intermediate radical ions or radicals, and the low activation barriers for follow-up reactions provide significant hurdles for the development of efficient catalytic photochemical processes that work under stereochemical control and provide chiral molecules in an asymmetric fashion. Here we report a highly efficient asymmetric catalyst that uses visible light for the necessary molecular activation, thereby combining asymmetric catalysis and photocatalysis. We show that a chiral iridium complex can serve as a sensitizer for photoredox catalysis and at the same time provide very effective asymmetric induction for the enantioselective alkylation of 2-acyl imidazoles. This new asymmetric photoredox catalyst, in which the metal centre simultaneously serves as the exclusive source of chirality, the catalytically active Lewis acid centre, and the photoredox centre, offers new opportunities for the 'green' synthesis of non-racemic chiral molecules.

show abstract

“…127 The oxidation step was carried out with visible light (blue LEDs) in MeCN with [Ru(bpy) 3 ]Cl 2 complex acting as the photocatalyst and CCl 4 as the oxidant. After the oxidation was complete, the solvent was switched to MTBE, which was more favorable for the Mannich reaction (racemic product was obtained if both steps were carried out in MeCN or other polar solvents).…”

Section: Cross-dehydrogenative Coupling Of Tertiary Aminesmentioning

confidence: 99%

Imine and iminium precursors as versatile intermediates in enantioselective organocatalysis

Kataja

Masson

2014

Tetrahedron

View full text Add to dashboard Cite

Photoredox activation and anion binding catalysis in the dual catalytic enantioselective synthesis of β-amino esters

Cited by 271 publications

References 71 publications

Intermolecular [3+2] Annulation of Cyclopropylanilines with Alkynes, Enynes, and Diynes via Visible Light Photocatalysis

Intermolecular [3+2] Annulation of Cyclopropylanilines with Alkynes, Enynes, and Diynes via Visible Light Photocatalysis

Asymmetric photoredox transition-metal catalysis activated by visible light

Imine and iminium precursors as versatile intermediates in enantioselective organocatalysis

Contact Info

Product

Resources

About