A Light‐Activated Olefin Metathesis Catalyst Equipped with a Chromatic Orthogonal Self‐Destruct Function

Sutar, Revannath L.; Levin, Efrat; Butilkov, Danielle; Goldberg, Israel; Reany, Ofer; Lemcoff, N. Gabriel

doi:10.1002/ange.201508966

Cited by 32 publications

(5 citation statements)

References 90 publications

(48 reference statements)

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“…The inherent chromatic orthogonality displayed between the isomerization reaction of the sulfur-chelated catalysts (photoactivation) and the removal of supersilyl ethers was further exploited in the design of a catalyst with an embedded self-destruction function, 21 - cis . 41 Although destruction of an active catalyst may seem to be a waste of a precious rare-metal catalyst, this function could be of great use in stereolithography, especially in layer-by-layer 3D printing processes. “Killing” the remaining active catalyst after polymerization and before applying a new layer of monomer/catalyst mixture may help in preventing loss of spatial resolution.…”

Section: Guiding Chemistry With Lightmentioning

confidence: 99%

“…(bottom) Polymerization of a norbornene derivative in metal molds with 21 - cis : (a) irradiation at 350 nm; (b) irradiation at 254 nm followed by UV-A. Reproduced with permission from ref ( 41 ). Copyright 2016 Wiley-VCH.…”

Section: Guiding Chemistry With Lightmentioning

confidence: 99%

“…47 - cis was designed with a chromatic-orthogonal self-destruct switch, similar to that of 21 - cis . 41 The kill switch in this case is based on the photosensitivity of the 2-nitrobenzyl phosphite ligand, and irradiation of 47 - cis with UV-C light led to rapid degradation of the catalyst. However, 47 - cis has additional advantages compared with 21 - cis .…”

Section: Photoactivation Of Ruthenium Phosphite Complexes For Olefin mentioning

confidence: 99%

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Light-Activated Olefin Metathesis: Catalyst Development, Synthesis, and Applications

et al. 2020

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Conspectus The most important means for tuning and improving a catalyst’s properties is the delicate exchange of the ligand shell around the central metal atom. Perhaps for no other organometallic-catalyzed reaction is this statement more valid than for ruthenium-based olefin metathesis. Indeed, even the simple exchange of an oxygen atom for a sulfur atom in a chelated ruthenium benzylidene about a decade ago resulted in the development of extremely stable, photoactive catalysts. This Account presents our perspective on the development of dormant olefin metathesis catalysts that can be activated by external stimuli and, more specifically, the use of light as an attractive inducing agent. The insight gained from a deeper understanding of the properties of cis -dichlororuthenium benzylidenes opened the doorway for the systematic development of new and efficient light-activated olefin metathesis catalysts and catalytic chromatic-orthogonal synthetic schemes. Following this, ways to disrupt the ligand-to-metal bond to accelerate the isomerization process that produced the active precatalyst were actively pursued. Thus, we summarize herein the original thermal activation experiments and how they brought about the discoveries of photoactivation in the sulfur-chelated benzylidene family of catalysts. The specific wavelengths of light that were used to dissociate the sulfur–ruthenium bond allowed us to develop noncommutative catalytic chromatic-orthogonal processes and to combine other photochemical reactions with photoinduced olefin metathesis, including using external light-absorbing molecules as “sunscreens” to achieve novel selectivities. Alteration of the ligand sphere, including modifications of the N-heterocyclic carbene (NHC) ligand and the introduction of cyclic alkyl amino carbene (CAAC) ligands, produced more efficient light-induced activity and special chemical selectivity. The use of electron-rich sulfoxides and, more prominently, phosphites as the agents that induce latency widened the spectrum of light-induced olefin metathesis reactions even further by expanding the colors of light that may now be used to activate the catalysts, which can be used in applications such as stereolithography and 3D printing of tough metathesis-derived polymers.

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Section: Guiding Chemistry With Lightmentioning

confidence: 99%

Section: Guiding Chemistry With Lightmentioning

confidence: 99%

Section: Photoactivation Of Ruthenium Phosphite Complexes For Olefin mentioning

confidence: 99%

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Light-Activated Olefin Metathesis: Catalyst Development, Synthesis, and Applications

et al. 2020

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“…Thus, by taking advantage of the wavelength selective photoactivation of these complexes, a regioselective chromatic orthogonal ring‐closing metathesis (RCM) protocol that could produce either dihydropyran or dihydrofuran compounds with excellent regio‐selectivity was achieved . The chromatic orthogonality between photocleavage of the sisyl ethers (UV‐C) and photoactivation of the catalyst (UV‐A) was also used in a novel strategy where sisyl groups were directly attached to the NHC ligand of the catalyst (catalyst B , Figure ), to make catalysts that can be activated with one wavelength and permanently deactivated with another . Notwithstanding the high efficacy of olefin metathesis, there are still some challenging reactions where routine olefin metathesis falls short .…”

Section: Figurementioning

confidence: 99%

Bichromatic Photosynthesis of Coumarins by UV Filter‐Enabled Olefin Metathesis

et al. 2017

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Herein, we report on a two-step bichromatic synthesis of coumarins involving UV-A and UV-C light. The first step is a UV-A photoinduced ruthenium catalyzed cross-metathesis (CM) reaction of 2-nitrobenzyl protected 2hydroxystyrenes with acrylates, using an external solution of 1-pyrene carboxaldehyde as a UV filter. Irradiation in the absence of the filter permanently inhibits the light activated catalyst due to photocleavage of the photolabile protecting group (PPG) and ensuing phenolate chelation to the ruthenium. The simple removal of the external filter after CM allows further photochemical reactions with UV-C light to achieve more complex architectures, such as the coumarins presented in this work.

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“…Notably, Ru–S chelation produced complexes with a cis -dichloro structure that rendered them inactive for most metathesis processes under ambient conditions (Figure ). These precatalysts could be activated by applying heat or light irradiation through a unique mechanism involving isomerization of the dormant cis -dichloro species into an active trans -dichloro configuration. ,, Further modifications, such as replacing the substituent on the chelating sulfur atom or exchanging the anionic ligands, also significantly altered the properties of the catalysts. ,,,,, Most importantly, the use of light in novel metathesis applications, including the 3D printing of ROMP polymers, the guiding of chromatically orthogonal chemical reactions, or their integration with plasmonic Au nanoparticles, has significantly boosted the study of these latent catalysts. ,− …”

Section: Introductionmentioning

confidence: 99%

Ruthenium Olefin Metathesis Catalysts with Six-Membered Chelating Dithioacetal Ligands: Synthesis and Reactivity

et al. 2023

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Ruthenium sulfur-chelated benzylidenes possessing five-membered chelating architectures exhibiting latency and excellent thermal and photochemical activation behavior in various metathesis reactions are well known. On the other hand, six-membered sulfur-Ru-chelates (Ru–S) are much rarer. Herein, we describe a study of the synthesis, characterization, and catalytic properties of four new cis-dichlorido ruthenium dithioacetal-chelated complexes. As expected for sulfur-chelated benzylidenes, the X-ray structures of the complexes disclosed cis-dichloro configurations for all the complexes. The catalytic profiles of these complexes were systematically studied for benchmark RCM and ROMP reactions and provided findings on latency and activation based on chelating dithioacetal groups.

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A Light‐Activated Olefin Metathesis Catalyst Equipped with a Chromatic Orthogonal Self‐Destruct Function

Cited by 32 publications

References 90 publications

Light-Activated Olefin Metathesis: Catalyst Development, Synthesis, and Applications

Light-Activated Olefin Metathesis: Catalyst Development, Synthesis, and Applications

Bichromatic Photosynthesis of Coumarins by UV Filter‐Enabled Olefin Metathesis

Ruthenium Olefin Metathesis Catalysts with Six-Membered Chelating Dithioacetal Ligands: Synthesis and Reactivity

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