High-level electronic structure calculations, including a continuum treatment of solvent, are employed to elucidate and quantify the effects of alkyl halide structure on the barriers of SN2 and E2 reactions. In cases where such comparisons are available, the results of these calculations show close agreement with solution experimental data. Structural factors investigated include α- and β-methylation, adjacency to unsaturated functionality (allyl, benzyl, propargyl, α to carbonyl), ring size, and α-halogenation and cyanation. While the influence of these factors on SN2 reactivity is mostly well-known, the present study attempts to provide a broad comparison of both SN2 and E2 reactivity across many cases using a single methodology, so as to quantify relative reactivity trends. Despite the fact that most organic chemistry textbooks say far more about how structure affects SN2 reactions than about how it affects E2 reactions, the latter are just as sensitive to structural variation as are the former. This sensitivity of E2 reactions to structure is often underappreciated.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

A Rh -catalyzed method for intermolecular alkylation of the β-C(sp )-H bond of enol ethers, enamides, and enecarbamates with α-diazo-1,3-dicarbonyl compounds is reported. The products are formed in up to 99 % yield and can be readily derivatized under a variety of conditions. By utilizing a combination of experimental and computational studies, the presumptive addition-elimination reaction mechanism was investigated and found to proceed under thermodynamic control at higher temperature. The acquired fundamental knowledge was translated into a strategic reaction design and yielded the first example of the β-C-H functionalizations of acyclic enol ethers using α-diazo-1,3-dicarbonyl compounds.

Syphilis is growing ever more prevalent in the United States with its incidence rising every year. Dermatopathologists need to maintain a high index of suspicion to avoid delayed diagnosis of this treatable disease. Accordingly, it is imperative to be aware of its myriad of presentations—including secondary syphilis with granulomatous inflammation. Most cases show aggregations of epithelioid histiocytes associated with plasma cells. Other patterns include an interstitial granuloma‐annulare‐like pattern, sarcoidal, and tuberculoid pattern. Immunohistochemical stains for Treponema pallidum may be negative, especially in late secondary or tertiary syphilis. We present a case of nodular secondary syphilis with granulomatous inflammation with negative T. pallidum staining.

Intermolecular C­(sp3)–H insertions of β-carbonyl ester dirhodium-carbenes are extremely rare. Toward developing efficient reactions of these carbenes, a model for their insertion into C­(sp3)–H bonds is described using density functional theory (DFT) calculations. In this study, the relevant electronic and steric components of β-carbonyl ester dirhodium-carbenes that affect intermolecular C­(sp3)–H activation energies are explored, parametrized, and used to construct an intuitive model for predicting propensity for C–H insertion. The resulting insights from the theoretical investigation are actualized through experiments to establish reactivity trends for these species and reaction discovery. On the basis of these integrated computational and experimental efforts, examples of intermolecular C­(sp3)–H insertions featuring secondary α-diazo-β-amide esters are reported. The resulting carbenes feature an intramolecular 1,6-hydrogen bond that affords increased stability and enhanced reactivity for C­(sp3)–H insertion as compared to other β-carbonyl ester dirhodium-carbenes. The reactivity of these carbenes is also highlighted through (1) an example of a cyclopropanation reaction and (2) the use of a chiral dirhodium catalyst system.