1440419-03-3Relevant articles and documents
Electrophile, Substrate Functionality, and Catalyst Effects in the Synthesis of α-Mono and Di-Substituted Benzylamines via Visible-Light Photoredox Catalysis in Flow
Vilé, Gianvito,Richard-Bildstein, Sylvia,Lhuillery, Arnaud,Rueedi, Georg
, p. 3786 - 3794 (2018)
We report herein the facile and one-pot synthesis of α-mono- and di-substituted benzylamines from cheap and readily available α-amino acids, via photocatalytic decarboxylative arylation in flow. This enables to access intermediates and building blocks that are difficult to obtain via other synthetic routes, but are key for the manufacture of pharmaceuticals, agrochemicals, and fine chemicals. The optimal decarboxylative conditions were identified through a high-throughput evaluation of catalysts, organic or inorganic bases, ligands, and reaction parameters (i. e., contact time, temperatures, and photoelectron power). The reaction turned out to be electronically controlled as the yields increased with increasing electron-density on the aryl moiety. The results were correlated with the redox properties of the photocatalysts, deriving catalyst structure-performance relationships which can facilitate the future identification of even better materials. In addition, compared to traditional batch chemistry, the use of a flow protocol led to quicker reactions (30 min instead of 12–72 h) and ensured more predictable reaction scale-ups.
Photoactive electron donor-acceptor complex platform for Ni-mediated C(sp3)-C(sp2) bond formation
Kammer, Lisa Marie,Badir, Shorouk O.,Hu, Ren-Ming,Molander, Gary A.
, p. 5450 - 5457 (2021/05/05)
A dual photochemical/nickel-mediated decarboxylative strategy for the assembly of C(sp3)-C(sp2) linkages is disclosed. Under light irradiation at 390 nm, commercially available and inexpensive Hantzsch ester (HE) functions as a potent organic photoreductant to deliver catalytically active Ni(0) species through single-electron transfer (SET) manifolds. As part of its dual role, the Hantzsch ester effects a decarboxylative-based radical generation through electron donor-acceptor (EDA) complex activation. This homogeneous, net-reductive platform bypasses the need for exogenous photocatalysts, stoichiometric metal reductants, and additives. Under this cross-electrophile paradigm, the coupling of diverse C(sp3)-centered radical architectures (including primary, secondary, stabilized benzylic, α-oxy, and α-amino systems) with (hetero)aryl bromides has been accomplished. The protocol proceeds under mild reaction conditions in the presence of sensitive functional groups and pharmaceutically relevant cores.
O-benzoylhydroxylamines as alkyl nitrene precursors: Synthesis of saturated N-heterocycles from primary amines
Noda, Hidetoshi,Asada, Yasuko,Shibasaki, Masakatsu
, p. 8769 - 8773 (2020/10/12)
We introduce O-benzoylhydroxylamines as competent alkyl nitrene precursors. The combination of readily available, stable substrates and a proficient rhodium catalyst provides a straightforward means for the construction of various pyrrolidine rings from the corresponding primary amines. Preliminary mechanistic investigation suggests that the structure of the nitrene precursor plays a role in determining the nature of the resulting reactive intermediate.
