573 research outputs found

    Recent Advances in the Chemistry of SmI2–H2O

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    Recent work from our laboratories has shown SmI2–H2O to be a versatile, readily-accessible and non-toxic reductant that is more powerful than SmI2. This review describes the reduction of functional groups that were previously thought to lie beyond the reach of SmI2 and complexity-generating cyclisations and cyclisation cascades triggered by the reduction of the ester carbonyl group with SmI2–H2O

    Copper-catalyzed functionalization of enynes.

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    From Europe PMC via Jisc Publications RouterHistory: ppub 2020-10-01, epub 2020-10-07Publication status: PublishedFunder: Engineering and Physical Sciences Research Council; Grant(s): EP/P001386/1, EP/M005062/1The copper-catalyzed functionalization of enyne derivatives has recently emerged as a powerful approach in contemporary synthesis. Enynes are versatile and readily accessible substrates that can undergo a variety of reactions to yield densely functionalized, enantioenriched products. In this perspective, we review copper-catalyzed transformations of enynes, such as boro- and hydrofunctionalizations, copper-mediated radical difunctionalizations, and cyclizations. Particular attention is given to the regiodivergent functionalization of 1,3-enynes, and the current mechanistic understanding of such processes

    Samarium(II) folding cascades involving hydrogen atom transfer for the synthesis of complex polycycles

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    The expedient assembly of complex, natural product-like small molecules can deliver new chemical entities with the potential to interact with biological systems and inspire the development of new drugs and probes for biology. Diversity-oriented synthesis is a particularly attractive strategy for the delivery of complex molecules in which the 3-dimensional architecture varies across the collection. Here we describe a folding cascade approach to complex polycyclic systems bearing multiple stereocentres mediated by reductive single electron transfer (SET) from SmI2. Simple, linear substrates undergo three different folding pathways triggered by reductive SET. Two of the radical cascade pathways involve the activation and functionalization of otherwise inert secondary alkyl and benzylic groups by 1,5-hydrogen atom transfer (HAT). Combination of SmI2, a privileged reagent for cascade reactions, and 1,5-HAT can lead to complexity-generating radical sequences that unlock access to diverse structures not readily accessible by other means

    A Sm(II)-mediated cascade approach to Dibenzoindolo[3,2-b]carbazoles:synthesis and evaluation

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    Previously unstudied dibenzoindolo[3,2-b]carbazoles have been prepared by two-directional, phase tag-assisted synthesis utilizing a connective-Pummerer cyclization and a SmI2-mediated tag cleavage-cyclization cascade. The use of a phase tag allows us to exploit unstable intermediates that would otherwise need to be avoided. The novel materials were characterized by X-ray, cyclic voltammetry, UV-vis spectroscopy, TGA, and DSC. Preliminary studies on the performance of OFET devices are also described