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  • Second-Generation Chiral Amino Acid Derivatives Afford High Stereoselectivity and Stability in Aqueous RNA Acylation. The Journal of organic chemistry Shioi, R., Chatterjee, S., Xiao, L., Zhong, W., Kool, E. T. 2024

    Abstract

    Activated acyl species have proven versatile in the esterification of 2'-OH groups in RNA, enabling structure mapping, caging, profiling, and labeling of the biopolymer. Nearly all reagents developed for this reaction have been achiral; however, a recent study reported that simple chiral amino acid acylimidazole derivatives could yield diastereoselective reactions at RNA 2'-OH in water, enabling up to 4:1 selectivity in screening. Here, we investigated the effect of steric bulk on the stereoselectivity of RNA reaction and on the stability of adducts with a library of 36 chiral acylimidazole scaffolds with increasing steric demand. The results document the highest stereoselectivity yet achieved in RNA acylation reactions, with as high as >99:1 diastereoselectivity at >70% conversion. Also notably, the bulky adducts were found to have markedly improved stability on RNA.

    View details for DOI 10.1021/acs.joc.4c00686

    View details for PubMedID 38809698

  • Selective Arylation of RNA 2'-OH Groups via SNAr Reaction with Trialkylammonium Heterocycles. Angewandte Chemie (International ed. in English) Chatterjee, S., Xiao, L., Zhong, W., Feng, S., Kool, E. T. 2024: e202403496

    Abstract

    Small-molecule reactions at the 2'-OH groups of RNA enable useful applications for transcriptome technology and biology. To date, all reactions have involved carbonyl acylation and mechanistically related sulfonylation, limiting the types of modifications and properties that can be achieved. Here we report that electron-deficient heteroaryl species selectively react with 2'-OH groups of RNA in water via SNAr chemistry. In particular, trialkyl-ammonium (TAA)-activated aromatic heterocycles, prepared in one step from aryl chloride precursors, give high conversions to aryl ether adducts with RNAs in aqueous buffer in ~2-3 h. Remarkably, a TAA triazine previously used only for reaction with carboxylic acids, shows unprecedented selectivity for RNA over water, reacting rapidly with 2'-OH groups while exhibiting a half-life in water of >10 days. We further show that a triazine aryl species can be used as a probe at trace-level yields to map RNA structure in vitro. Finally, we prepare a number of functionalized trialkylammonium triazine reagents and show that they can be used to covalently label RNA efficiently for use in vitro and in living cells. This direct arylation chemistry offers a simple and distinct structural scaffold for post-synthetic RNA modification, with the potential for utility in multiple applications in transcriptome research.

    View details for DOI 10.1002/anie.202403496

    View details for PubMedID 38625814