Silver ion-assisted solvolysis of phenacyl halides in aqueous ethanol

Pasto, Daniel J.; Garves, K.

doi:10.1021/jo01278a058

Cited by 14 publications

(3 citation statements)

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“…For example, the solvolysis of ethyl bromide showed >5000-fold rate enhancement when assisted by silver salts. 23 However, surprisingly little is known about the impact of silver salts on displacement reactions with α-haloacetamides, in analogy to the submonomer peptoid synthesis displacement reaction. In the closest reported example, the rate of solvolysis of phenacyl bromide in aqueous ethanol in the presence of AgClO 4 was enhanced by >500-fold as compared to the reaction without silver.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…In the closest reported example, the rate of solvolysis of phenacyl bromide in aqueous ethanol in the presence of AgClO 4 was enhanced by >500-fold as compared to the reaction without silver. 23 Inspired by these results, we investigated the impact of silver perchlorate on the displacement of resin-bound bromoacetylated peptoids with aniline submonomers. Model bromoacetylated tetrapeptoid 2 was synthesized and treated on resin with 4-(CF 3 )aniline as a representative electron-poor aniline in the presence of 3 equiv of AgClO 4 in different solvents (Table 1).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Accelerated Submonomer Solid-Phase Synthesis of Peptoids Incorporating Multiple Substituted N-Aryl Glycine Monomers

et al. 2015

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N-Aryl glycines are a chemically diverse class of peptoid monomers that have strong structure-inducing propensities. Yet their use has been limited due to the sluggish reactivity of the weakly nucleophilic aniline submonomers. Here, we report up to a 76-fold rate acceleration of the displacement reaction using aniline submonomers in solid-phase peptoid synthesis. This is achieved by adding halophilic silver salts to the displacement reaction, facilitating bromide abstraction and AgBr precipitation. Mechanistic insight derived from analysis of a series of 15 substituted anilines reveals that the silver-mediated reaction proceeds through a transition state that has considerably less positive charge buildup on the incoming nucleophile and an enhanced leaving group. This straightforward enhancement to the submonomer method enables the rapid room temperature synthesis of a wide variety of N-aryl glycine-rich peptoid oligomers, possessing both electron-withdrawing and -donating substituents, in good yields.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Accelerated Submonomer Solid-Phase Synthesis of Peptoids Incorporating Multiple Substituted N-Aryl Glycine Monomers

et al. 2015

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“…The crude product (668 mg) obtained after concentration was purified on column chromatography (ca. 20 g of silica gel: elutant, hexane/ether 90/10)12 to give the title compound (636 mg, 86%) as a slightly yellow oil, which on cooling crystallized: mp (hexane) 34.0-34.5 °C;1:i IR (neat) 1685 cm-1 (vs, C=0); NMR (CC14) 4.25 (s, 2 H, CH2ICO-), 7.28-7.65 (m, 3 H, aromatic), 7.87-8.10 ppm (m, 2 H, aromatic); MS m/e (rel intensity) 246 ( +•, 18), 119 (M+--I, 13), 105 (M+. -CH2I, 20), 77 (Ph+, 100), 51 (M+--C2H2CO-H2I, 40).…”

Section: Methodsmentioning

confidence: 99%