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1. Contrasteric Glycosylations of Cotylenol and 1,2-Diols by Virtual Linker Selection

   https://doi.org/10.1021/jacs.4c15719  

   Snelson, Dylan W; Ting, Stephen I; Shenvi, Ryan A (January 2025, Journal of the American Chemical Society)

   Many terpene glycosides exhibit contrasteric patterns of 1,2-diol glycosylation in which the more hindered alcohol bears a sugar; protection of the less hindered alcohol only increases steric repulsion. Here, we report a method for contrasteric glycosylation using a new sugar-linker that forms a cleavable, 10-membered ring with high efficiency, leading to syntheses of cotylenin E, J, and ISIR-050. Linker selection was aided by DFT calculations of side reactions and stereoselectivity, as well as conformational analyses using autoDFT, a Python script that converts SMILES strings to DFT-optimized conformational ensembles. 

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2. Demonstration of a Stereospecific Photochemical Meta Effect

   https://doi.org/10.3390/photochem2010006  

   Pham, Hoai; Hunsley, Madelyn; Yang, Chou-Hsun; Wang, Haobin; Reed, Scott M. (March 2022, Photochem)

   A fundamental goal of photochemistry is to understand how structural features of a chromophore can make specific bonds within a molecule prone to cleavage by light, or photolabile. The meta effect is an example of a regiochemical explanation for photolability, in which electron donating groups on an aromatic ring cause photolability selectively at the meta position. Here, we show, using a chromophore containing one ring with a meta-methoxy group and one ring with a para-methoxy group, that two stereoisomers of the same compounds can react with light differently, based simply on the three-dimensional positioning of a meta anisyl ring. The result is that the stereoisomers of the compound with the same configuration at both stereogenic centers are photolabile while the stereoisomers with opposite configuration do not react with light. Furthermore, time-dependent density functional theory (TD-DFT) calculations show distinct excitation pathways for each stereoisomer. 

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3. Structure determination of a bis[4-(di- n -butylamino)phenyl](pyridin-3-yl)borane tetramer highlighting a unique geometric conformation of the core 16-membered ring

   https://doi.org/10.1107/S2053229623002619  

   Lovstedt, Alex; Dempsey, Stephen H.; Kass, Steven R. (May 2023, Acta Crystallographica Section C Structural Chemistry)

   The tetramer of bis(4-di- n -butylaminophenyl)(pyridin-3-yl)borane [systematic name: 2λ 4 ,4λ 4 ,6λ 4 ,8λ 4 -tetrabora-1,3,5,7(1,3)-tetrapyridinacyclooctaphane-1 1 ,3 1 ,5 1 ,7 1 -tetrakis(ylium)], C 132 H 192 B 4 N 12 , was synthesized unexpectedly and crystallized. Its structure contains an unusual 16-membered ring core made up of four (pyridin-3-yl)borane groups. The ring adopts a conformation with pseudo- S 4 symmetry that is very different from the two other reported examples of this ring system. Density functional theory (DFT) computations indicate that the stability of the three reported ring conformations is dependent on the substituents on the B atoms, and that the pseudo- S 4 geometry observed in the bis(4-dibutylaminophenyl)(pyridin-3-yl)borane tetramer becomes significantly more stable when phenyl or 2,6-dimethylphenyl groups are attached to the boron centers. 

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4. A cheap metal catalyzed ring expansion/cross-coupling cascade: a new route to functionalized medium-sized and macrolactones

   https://doi.org/10.1039/d2sc06157k  

   Liu, Shuai; Ma, Pengchen; Zhang, Lu; Shen, Shenyu; Miao, Hong-Jie; Liu, Le; Houk, K. N.; Duan, Xin-Hua; Guo, Li-Na (May 2023, Chemical Science)

   A Cu or Fe-catalyzed radical ring expansion/coupling cascade was developed. It provides a new access to medium-sized and macrolactones with CN, N₃, SCN, and X groups. DFT calculations suggest a Cu(i)/Cu(ii)/Cu(iii) catalytic cycle for the cyanation. 

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5. Computational mapping of redox-switchable metal complexes based on ferrocene derivatives

   https://doi.org/10.1039/C9CC01977D  

   Lai, Amy; Clifton, Jamie; Diaconescu, Paula L.; Fey, Natalie (June 2019, Chemical Communications)

   DFT calculations were used to capture the properties of redox-switchable metal complexes relevant to the ring-opening polymerisation of cyclic esters by varying the metals, donors, linkers, and substituents in both accessible ferrocene oxidation states. A map of this chemical space highlights that modifying the ligand architecture and the metal has a larger impact on structural changes than changing the oxidation state of the ferrocene backbone. 

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