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1. Command-destruct thermosets via photoinduced thiol-catalyzed β-scission of acyclic benzylidene acetals

   https://doi.org/10.1039/D0PY01006E  

   Walker, William D.; Sandoz, Michael J.; Roland, Samuel; Buster, Tony M.; Newman, John K.; Patton, Derek L. (November 2020, Polymer Chemistry)

   null (Ed.)

   Photoinduced thiol-catalyzed hydrogen abstraction and β-scission of acyclic benzylidene acetals is demonstrated as a new route to “command-destruct” polymer thermosets. Using this approach, we show that poly(thioether acetal) networks synthesized via thiol–ene photopolymerization rapidly degrade to alkyl benzoate byproducts when triggered with light, transitioning from solid to liquid within seconds. The light-driven construction and destruction processes, accessible via distinct differences in kinetics, are readily amenable for photopatterning, additive/subtractive manufacturing and wavelength-selective applications. 

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2. Stereoselective syntheses of 2-methyl-1,3-diol acetals via Re-catalyzed [1,3]-allylic alcohol transposition

   https://doi.org/10.1039/d2sc07059f  

   Liu, Jiaming; Chen, Ming (August 2023, Chemical Science)

   Rhenium-catalyzed stereoselective transposition of allylic alcohols is reported. In the presence of 1 mol% of Re 2 O 7 , ( E )- or ( Z )-δ-hydroxymethyl- anti -homoallylic alcohols were converted into the acetals of 2-methyl-1,3- syn -diols with excellent diastereoselectivities. 1,3- syn -Diol acetals can also be synthesized from ( E )-δ-hydroxymethyl- syn -homoallylic alcohols. 

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3. The impact of metal coordination on the assembly of bis(indolyl)methane-naphthalene-diimide amphiphiles

   https://doi.org/10.1039/D0DT02732D  

   Bayindir, Sinan; Lee, Kwang Soo; Saracoglu, Nurullah; Parquette, Jon R. (October 2020, Dalton Transactions)

   null (Ed.)

   The self-assembly and coordination of amphiphiles comprised of naphthalenediimide (NDI) and bis(indolyl)methane (BIM) chromophores were investigated as a function of pH and metal. As observed by TEM, SEM and AFM imaging, the self-assembly of NDI-BIM 1 produced irregular nanostructures at neutral pH in CH 3 CN–H 2 O (1 : 1); whereas, well-defined nanotubes were observed at pH 2. Conversely, Fmoc-protected, NDI-BIM 2 formed nanotubes at neutral pH and nonspecific aggregates at pH 2. Upon coordination of Cu 2+ ions to the bis(indoyl)methane moiety, a reorganization from nanotubes to vesicular structures was observed. 

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4. Ring Expansion via One-Pot Conversion of Lactone Acetals to Cyclic Enones. Synthesis of (±)-1- epi -Xerantholide

   https://doi.org/10.1021/acs.orglett.4c02855  

   Salvatierra, Jose; Silberberg, Natalie A; Minehan, Thomas G (October 2024, Organic Letters)

   Baeyer-Villiger oxidation of alpha-alkoxy ketones 1 provides lactone acetals 2, which react with the lithium salts of di-methyl(alkyl) phosphonates in the presence of LaCl3•2LiCl to provide cyclic enones 3 in good to excellent yields after treatment with dilute aqueous potassium carbonate. Thus, five-, six-, and seven-membered lactones are con-verted to five-, six-, and seven membered cyclic enones. The utility of this two-step ring expansion method is demonstrated in the synthesis of (±)-1-epi-xerantholide from 5-methyl-2-cyclohexen-1-one. 

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5. C–H functionalization of indole with diazoacetate catalyzed by a CCC-NHC Ir (III) dimer complex

   https://doi.org/10.1016/j.tetlet.2023.154610  

   Rawat, Maitreyee; Hollis, T. Keith (July 2023, Tetrahedron Letters)

   The first catalytic application of a CCC-NHC pincer Ir (III) dimer complex for the C – H functionalization of N-methylindoles with a-aryl-a-diazoacetates at the C-3 position is reported herein. The Ir pincer dimer complex was used as a catalyst at 3 mol% loading. The best reaction conditions involved a combination of catalyst and substrates in a specific order. It resulted in the activation of the C–H bond with the formation of a new C–C bond to generate a-aryl-a-indolyl acetates with more than 99% conversion at room temperature without requiring any additives. Isolated yields of 84–97% were obtained for a range of substrates. Under these catalytic conditions, the unprotected N–H indoles did not react with a-aryl-a-diazoacetate. These catalytic conditions provided an efficient synthetic route to the synthesis of a-aryl-a-indolyl acetates. 

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