Umpolung Synthesis of Diarylmethylamines <i>via</i> Palladium‐ Catalyzed Arylation of <i>N</i>‐Benzyl Aldimines

Li, Minyan; Yucel, Baris; Jiménez, Jacqueline; Rotella, Madeline; Fu, Yingjuan; Walsh, Patrick J.

doi:10.1002/adsc.201600075

Cited by 35 publications

(12 citation statements)

References 32 publications

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“…12–15 Under these conditions, deprotonation of the product was not observed, as judged by the absence of isomerized product (ArAr′C=NCHPh 2 ). 19,29 Key to preventing product deprotonation was the use of hindered bases [MN(SiMe 3 ) 2 (M = Li, Na)] at room temperature.…”

Section: Resultsmentioning

confidence: 96%

“…Our team, 12–15 and others, 16–21 have been interested in the synthesis of amines via an umpolung approach involving the functionalization of 2-azaallyl anions. Recently, we reported the synthesis of both allylic amines and enamines through the transition-metal catalyzed arylation of 1,1-diphenyl-3-arylallyl-2-azaallyl anions (shown retrosynthetically in Figure 1a, path a).…”

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confidence: 99%

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Transition-metal-free chemo- and regioselective vinylation of azaallyls

Gutiérrez

Berritt

et al. 2017

Nature Chem

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Direct C(sp3)–C(sp2) bond-formation under transition-metal-free conditions offers an atom-economical, inexpensive, and environmentally benign alternative to traditional transition metal-catalyzed cross-coupling reactions. A new chemo- and regioselective coupling protocol between 3-aryl-substituted-1,1-diphenyl-2-azaallyl derivatives and vinyl bromides has been developed. This is the first transition-metal-free cross-coupling of azaallyls with vinyl bromide electrophiles and delivers allylic amines in excellent yields (up to 99%). This relatively simple and mild protocol offers a direct and practical strategy for the synthesis of high-value allylic amine building blocks that does not require the use of transition metals, special initiators, or photoredox catalysts. Radical clock experiments, EPR studies and DFT calculations point to an unprecedented substrate-dependent coupling mechanism. Furthermore, an EPR signal was observed when the N-benzyl benzophenone ketimine was subjected to silylamide base, supporting formation of radical species upon deprotonation. The unique mechanisms outlined herein could pave the way for new approaches to transition-metal-free C–C bond formations.

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Section: Resultsmentioning

confidence: 96%

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confidence: 99%

Transition-metal-free chemo- and regioselective vinylation of azaallyls

Gutiérrez

Berritt

et al. 2017

Nature Chem

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“…A long alkyl chain was introduced onto the P m PV backbone to assure the resulting polymer P1 has good solubility in common organic solvents. Initial reactions were conducted in 24-well plates on 10 µmol scale by adapting small molecule high-throughput experimentation (HTE) 41 – 48 techniques to polymerizations (see Supplementary Method, High-Throughput Experimentation screenings for polymerization for full details). As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Sulfenate anions as organocatalysts for benzylic chloromethyl coupling polymerization via C=C bond formation

Berritt

Wang

et al. 2018

Nat Commun

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Organocatalytic polymerization reactions have a number of advantages over their metal-catalyzed counterparts, including environmental friendliness, ease of catalyst synthesis and storage, and alternative reaction pathways. Here we introduce an organocatalytic polymerization method called benzylic chloromethyl-coupling polymerization (BCCP). BCCP is catalyzed by organocatalysts not previously employed in polymerization processes (sulfenate anions), which are generated from bench-stable sulfoxide precatalysts. The sulfenate anion promotes an umpolung polycondensation via step-growth propagation cycles involving sulfoxide intermediates. BCCP represents an example of an organocatalyst that links monomers by C=C double bond formation and offers transition metal-free access to a wide variety of polymers that cannot be synthesized by traditional precursor routes.

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“…8 These intermediates react with a variety of electrophiles resulting in C-C bond formation (Scheme 1A). 4,[7][8][9][10][11][12] Recently, however, this umpolung reagent was found to activate electrophiles through one-electron processes (Scheme 1B). Using EPR spectroscopy, computational studies, and radical trapping experiments, our team demonstrated the activation of aryl, alkyl, and vinyl halides through single electron transfer (SET) pathways.…”

Section: Introductionmentioning

confidence: 99%