Robby Vroemans

Synthesis
DOI: 10.1055/s-0040-1720054

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© Georg Thieme Verlag Stuttgart · New York

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In the synthesis of alternating polyisocyanate copolymer by anionic polymerization, the (S)-(−)-α-methylbenzyl isocyanate and allyl isocyanate are incorporated into anionic propagation sites in an alternating fashion. The ammonium thiols are introduced to the allyl group to achieve the Janus amphiphilic helical conformation of polyisocyanate. Polyisocyanate mimics the structure and antibacterial activity of amphiphilic helical peptides, as described by Jiwon Seo, Eunji Lee, Jae-Suk Lee, and co-workers in their Research Article (e202212398).

Synthesis
DOI: 10.1055/s-0040-1720037

Over more than five decades, Alain Krief’s career has encompassed many contributions to chemistry, notably in his innovative work in the areas of organic synthesis and the use of inorganic and organic reagents, as well as his work on bioorganic chemistry and applications of information technology in chemistry. His research on the synthesis of cyclopropanes, including chrysanthemic acid and other pyrethroids, and the uses of selenium compounds in organic synthesis, have been of particular importance and have found widespread applications. In addition, his roles in international collaborations in research and his leadership of the International Organization for Chemical Sciences in Development from 2009 to 2020 have marked his strong commitment to the importance of chemistry as a science for the benefit of society and a contributor to the goal of sustainable development.1 Introduction2 A Spectrum of Research3 Leadership of the International Organization for Chemical Sciences in Development (IOCD)
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

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Nature Chemistry, Published online: 12 December 2022; doi:10.1038/s41557-022-01101-0

Nature, Published online: 08 December 2022; doi:10.1038/d41586-022-04375-z

Nature, Published online: 07 December 2022; doi:10.1038/d41586-022-04252-9

Isocyanide-based Multicomponent Reactions in a new light! A review about challenges, potentialities, new trends, and future directions of exploiting isocyanide unique reactivity features under visible light irradiation.

Abstract

Isocyanide-based multicomponent reactions claim a one century-old history of flourishing developments. On the other hand, the enormous impact of recent progresses in visible light photocatalysis has boosted the identification of new straightforward and green approaches to both new and known chemical entities. In this context, the application of visible light photocatalytic conditions to multicomponent processes has been promoting key stimulating advancements. Spanning from radical-polar crossover pathways, to photoinduced and self-catalyzed transformations, to reactions involving the generation of imidoyl radical species, the present literature analysis would provide a general and critical overview about the potentialities and challenges of exploiting isocyanides in visible light photocatalytic multicomponent reactions.

Publication date: 9 January 2023

Source: Tetrahedron, Volume 130

Author(s): Christopher E. Reimann, Kelly E. Kim, Alexander W. Rand, Farbod A. Moghadam, Brian M. Stoltz

Single and selective C−F bond activation of trifluoromethyl ketones using visible-light photoredox catalysis is achieved in a divergent fashion. Trapping of photo-catalytically generated difluoromethyl radical to various styrene derivatives benefitted with the formation of two essential classes of difluoromethyl-containing tetrahydrofuran-ring and linear ketones in a divergent fashion. State-of-the-art dispersion-corrected DFT calculations strongly support the proposed mechanistic pathway for this novel transformation.

Abstract

Selective defluorinative functionalization of trifluoromethyl ketones is a long-standing challenge owing to the exhaustive mode of the process. To meet the demands for the installation of the gem-difluoromethylene unit for the construction of the molecular architectures of well-known pharmaceuticals and agrochemicals, a distinct pathway is thereby highly desirable. Here, a protocol is introduced that allows the divergent synthesis of gem-difluoromethylene group containing tetrahydrofuran derivatives and linear ketones via single C−F bond activation of trifluoromethyl ketones using visible-light photoredox catalysis in the presence of suitable olefins as trapping partner. The choice of appropriate solvent and catalyst plays a significant role in controlling the divergent behavior of this protocol. Highly reducing photo-excited catalysts are found to be responsible for the generation of α,α-difluoromethyl ketone (DFMK) radicals as the key intermediate via a SET process. This protocol also results in a high diastereoselectivity towards the formation of partially fluorinated cyclic ketal derivatives with simultaneous construction of one C−C and two C−O bonds. State-of-the-art DFT calculations are performed to address the origin of diastereoselectivity as well as the divergence of this protocol.

Synthesis
DOI: 10.1055/a-1946-0512

Visible light photocatalysis has evolved into a promising mild and sustainable strategy to access radicals. This field unlocks formerly challenging or even previously inaccessible organic transformations. In this review, an overview of some lesser-known modes of photochemical activation of organic molecules and several emerging techniques within the versatile field of visible light photocatalysis are discussed. These are illustrated by selected photocatalytic reactions, with particular attention given to the reaction mechanism.1 Introduction2 Advanced Photoactivation Modes2.1 Photoinduced Hydrogen-Atom Transfer2.2 Proton-Coupled Electron Transfer2.3 Electron Donor-Acceptor Photoactivation of Organic Substrates2.4 Excited-State Transition Metal Catalysis3 Emerging Techniques3.1 Dual Catalysis3.2 Excited Radical Ion Photocatalysis3.3 Upconversion Strategies and Other Two-Photon Mechanisms3.4 Red and Near-Infrared Photocatalysis4 Conclusions and Outlook
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

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