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1. Focused ortho -Lithiation and Functionalization of p -Bromo- and p -Iodoanisole: Focused ortho -Lithiation and Functionalization of p -Bromo- and p -Iodoanisole

   https://doi.org/10.1002/ejoc.201800616  

   Slocum, D. W. ; Jennings, John A. ; Reinscheld, Thomas K. ; Whitley, Paul E. ( August 2018 , European Journal of Organic Chemistry)
2. Photoelectron spectroscopy and thermochemistry of o -, m -, and p -methylenephenoxide anions

   https://doi.org/10.1039/C8CP05403G  

   Nelson, Daniel J. ; Gichuhi, Wilson K. ; Nichols, Charles M. ; Bierbaum, Veronica M. ; Lineberger, W. Carl ; Lehman, Julia H. ( October 2018 , Physical Chemistry Chemical Physics)

   The anionic products following (H + H + ) abstraction from o -, m -, and p -methylphenol (cresol) are investigated using flowing afterglow-selected ion flow tube (FA-SIFT) mass spectrometry and anion photoelectron spectroscopy (PES). The PES of the multiple anion isomers formed in this reaction are reported, including those for the most abundant isomers, o -, m - and p -methylenephenoxide distonic radical anions. The electron affinity (EA) of the ground triplet electronic state of neutral m -methylenephenoxyl diradical was measured to be 2.227 ± 0.008 eV. However, the ground singlet electronic states of o - and p -methylenephenoxyl were found to be significantly stabilized by their resonance forms as a substituted cyclohexadienone, resulting in measured EAs of 1.217 ± 0.012 and 1.096 ± 0.007 eV, respectively. Upon electron photodetachment, the resulting neutral molecules were shown to have Franck–Condon active ring distortion vibrational modes with measured frequencies of 570 ± 180 and 450 ± 80 cm −1 for the ortho and para isomers, respectively. Photodetachment to excited electronic states was also investigated for all isomers, where similar vibrational modes were found to be Franck–Condon active, and singlet–triplet splittings are reported. The thermochemistry of these molecules was investigated using FA-SIFT combined with the acid bracketing technique to yield values of 341.4 ± 4.3, 349.1 ± 3.0, and 341.4 ± 4.3 kcal mol −1 for the o -, m -, and p -methylenephenol radicals, respectively. Construction of a thermodynamic cycle allowed for an experimental determination of the bond dissociation energy of the O–H bond of m -methylenephenol radical to be 86 ± 4 kcal mol −1 , while this bond is significantly weaker for the ortho and para isomers at 55 ± 5 and 52 ± 5 kcal mol −1 , respectively. Additional EAs and vibrational frequencies are reported for several methylphenyloxyl diradical isomers, the negative ions of which are also formed by the reaction of cresol with O − . 

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3. Parallel phylogeography of Prochlorococcus and Synechococcus

   https://doi.org/10.1038/s41396-018-0287-6  

   Kent, Alyssa G. ; Baer, Steven E. ; Mouginot, Céline ; Huang, Jeremy S. ; Larkin, Alyse A. ; Lomas, Michael W. ; Martiny, Adam C. ( October 2018 , The ISME Journal)

   The globally abundant marine Cyanobacteria Prochlorococcus and Synechococcus share many physiological traits but presumably have different evolutionary histories and associated phylogeography. In Prochlorococcus, there is a clear phylogenetic hierarchy of ecotypes, whereas multiple Synechococcus clades have overlapping physiologies and environmental distributions. However, microbial traits are associated with different phylogenetic depths. Using this principle, we reclassified diversity at different phylogenetic levels and compared the phylogeography. We sequenced the genetic diversity of Prochlorococcus and Synechococcus from 339 samples across the tropical Pacific Ocean and North Atlantic Ocean using a highly variable phylogenetic marker gene (rpoC1). We observed clear parallel niche distributions of ecotypes leading to high Pianka’s Index values driven by distinct shifts at two transition points. The first transition point at 6°N distinguished ecotypes adapted to warm waters but separated by macronutrient content. At 39°N, ecotypes adapted to warm, low macronutrient vs. colder, high macronutrient waters shifted. Finally, we detected parallel vertical and regional single-nucleotide polymorphism microdiversity within clades from both Prochlorococcus and Synechococcus, suggesting uniquely adapted populations at very specific depths, as well as between the Atlantic and Pacific Oceans. Overall, this study demonstrates that Prochlorococcus and Synechococcus have shared phylogenetic organization of traits and associated phylogeography.

    

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4. Stereoselective Synthesis of ( E )- and ( Z )-Isocyanoalkenes

   https://doi.org/10.1021/acs.orglett.2c03461  

   Tian, Huan ; Holyoke, Caleb W. ; Fleming, Fraser F. ( December 2022 , Organic Letters)
5. Relative hydrophilicities of cis and trans formamides

   https://doi.org/10.1073/pnas.1911331116  

   Li, Yong-Sheng ; Escobar, Luis ; Zhu, Yu-Jie ; Cohen, Yoram ; Ballester, Pablo ; Rebek, Julius ; Yu, Yang ( October 2019 , Proceedings of the National Academy of Sciences)

   Secondary formamides are widely encountered in biology and exist as mixtures of both cis and trans isomers. Here, we assess hydrophilicity differences between isomeric formamides through direct competition experiments. Formamides bearing long aliphatic chains were sequestered in a water-soluble molecular container having a hydrophobic cavity with an end open to the aqueous medium. NMR spectroscopic experiments reveal a modest preference (<1 kcal/mol) for aqueous solvation of the trans formamide terminals over the cis isomers. With diformamides, the supramolecular approach allows staging of intramolecular competition between short-lived species with subtle differences in hydrophobic properties. 

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