Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• both within the context of a classic gold π-activation/protodeauration mechanism and a general acid-catalyzed mechanism without intermediate gold alkyls. Keywords: alkene hydroamination; general acid catalysis; gold catalysis; isotope effect; phosphine ligand effect; solvent effect; Introduction

• against turnover protodeauration, they indicate strong parallels to general acid catalysis. There is little doubt that gold is required for the transformation, but the combination of solvent and substrate effects suggest that instead of acting as a specific alkene activator, it may instead create

• characterized as general acid catalysis (without invoking gold alkyl intermediates). Although many facets of this reaction remain to be understood, there are many practical implications of our work. For example, future catalyst optimization should focus on designing ligands that create more electrophilc gold

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• ). Both the pH of the medium (specific acid catalysis) and general acid catalysis by the ammonium groups of F-1 were potentially important for the ring opening reactions. The ring openings were conducted in three different media: neat methanol, a mixture of methanol and dichloromethane, and a mixture of

• × 10−2 M in water. Assuming that the average pKa value of the ammonium groups of the protonated form of TAPM was around 4.0, the pH value of the solution would be between 4 and 5. It is therefore most likely that F-1 operated via the general acid catalysis mechanism in this solvent mixture. As the pKa

• value of anilinium cations will only change to a small extent when the solvent is changed from water to methanol, the same general acid catalysis mechanism would be expected to occur in reactions carried out in methanol. For comparison, the commercially available (and most often used heterogeneous

Tuning the stability of alkoxyisopropyl protection groups

• Zehong Liang,
• Henna Koivikko,
• Mikko Oivanen and
• Petri Heinonen

Beilstein J. Org. Chem. 2019, 15, 746–751, doi:10.3762/bjoc.15.70

• . The vinyl ether hydrolysis has earlier shown to be even a subject of general acid catalysis [13][14]. It is useful to compare the stabilities of the acetal protections to those of the 4,4’-dimethoxytrityl protecting group used in oligonucleotide synthesis. Directly comparable data are hard to find

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• nucleotide are extensively used in mechanistic studies of protein nucleases and ribozymes. Rate accelerating 3´-bridging substitution has been used to find out whether the chemical step really is rate-liming and 5´-substitution to verify that some small ribozymes utilize general acid catalysis [40]. The

• linkage has undergone rapid initial protonation. In other words, a monoanionic phosphorane is obtained by a specific acid/general base mechanism that is experimentally equivalent to general acid catalysis. The monoanionic phosphorane is stable enough to pseudorotate and may, hence, undergo isomerization

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

• Eric V. Anslyn

Beilstein J. Org. Chem. 2016, 12, 362–376, doi:10.3762/bjoc.12.40

• synthetic receptors we created were designed to answer basic science questions about enzyme mechanisms [19][47], rate enhancements from ion-pairing and general acid-catalysis [48], as well as reveal the strengths of hydrogen bonding. Interspersed among this work using synthetic receptors there was a