Photoinduced Proton‐Transfer Reactions for Mild O‐H Functionalization of Unreactive Alcohols
作者:Sripati Jana、Zhen Yang、Fang Li、Claire Empel、Junming Ho、Rene M. Koenigs
DOI:10.1002/anie.201915161
日期:2020.3.27
hexafluoroisopropanol and the diazoalkane acts as an unreactive hydrogen‐bonding complex. Only after photoexcitation does this complex undergo a protonation‐substitution reaction to the reaction product. Investigations on the applicability of this photochemical transformation show that a broad variety of acidic alcohols can be subjected to this transformation and thus demonstrate the feasibility of
Scope and Mechanism of a True Organocatalytic Beckmann Rearrangement with a Boronic Acid/Perfluoropinacol System under Ambient Conditions
作者:Xiaobin Mo、Timothy D. R. Morgan、Hwee Ting Ang、Dennis G. Hall
DOI:10.1021/jacs.8b01618
日期:2018.4.18
enylboronic acid were identified as efficient catalysts for the direct and chemoselective activation of oxime N-OH bonds in the Beckmann rearrangement. This classical organic reaction provides a unique approach to prepare functionalized amide products that may be difficult to access using traditional amide coupling between carboxylic acids and amines. Using only 5 mol % of boronic acid catalyst and
Photochemical O−H Functionalization Reactions of Cyclic Diazoamides
作者:Claire Empel、Dennis Verspeek、Sripati Jana、Rene M. Koenigs
DOI:10.1002/adsc.202000818
日期:2020.11.4
Herein, we describe the photochemical O−H functionalization reaction of acidic alcohols with cyclic diazoamides. We studied the O−H functionalization reaction of different fluorinated and non‐fluorinated alcohols to give the corresponding ether products in high yields (43 examples, up to 97% yield). Furthermore, we performed studies to evaluate a photoexcited proton transfer reaction pathway in comparison
Late-Stage β-C(sp<sup>3</sup>)–H Deuteration of Carboxylic Acids
作者:Alexander Uttry、Sourjya Mal、Manuel van Gemmeren
DOI:10.1021/jacs.1c06474
日期:2021.7.28
Carboxylicacids are highly abundant in bioactive molecules. In this study, we describe the late-stage β-C(sp3)–H deuteration of freecarboxylicacids. On the basis of the finding that C–H activation with our catalysts is reversible, the de-deuteration process was first optimized. The resulting method uses ethylenediamine-based ligands and can be used to achieve the desired deuteration when using a
Proton or Carbene Transfer? On the Dark and Light Reaction of Diazoalkanes with Alcohols
作者:Claire Empel、Chao Pei、Feifei He、Sripati Jana、Rene M. Koenigs
DOI:10.1002/chem.202104397
日期:2022.3.10
O-H Functionalization: In this combined experimental and computational study, the reaction of diaryl diazoalkanes with alcohols is reported. In the ground state, a direct proton transfer governs reactivity with acidic HFIP. On the contrary, photoexcitation leads to formation of a triplet carbene intermediate that undergoes an alcohol-assisted intersystem crossing to a solvent-stabilized carbene that