Metal‐Free, Aerobic Dioxygenation of Alkenes Using Hydroxamic Acids

Schmidt, Valerie A.; Alexanian, Erik J.

doi:10.1002/anie.201000843

Cited by 130 publications

(22 citation statements)

References 36 publications

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“…In accordance with this free-radical mechanism, Schmidt and Alexanian more recently reported the aerobic dioxygenation of alkenyl N -aryl hydroxamic acids (Scheme 6) [21]. In this case dioxygenation proceeded under 1 atmosphere of O 2 alone, without any additional initiator being required.…”

Section: Reviewmentioning

confidence: 77%

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

Melone¹,

Punta²

2013

Beilstein J. Org. Chem.

151

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SummarySince the beginning of the century, N-hydroxyphthalimide and related compounds have been revealed to be efficient organocatalysts for free-radical processes and have found ample application in promoting the aerobic oxidation of a wide range of organic substrates. When combined with different co-catalysts, they are activated to the corresponding N-oxyl radical species and become able to promote radical chains, involving molecular oxygen, directly or indirectly. Most of the examples reported in the literature describe the use of these N-hydroxy derivatives in the presence of transition-metal complexes. However, eco-friendly standards, including the demand for highly selective transformations, impose the development of metal-free processes, especially for large-scale productions, as in the case of the oxygenation of hydrocarbons. For this reason, many efforts have been devoted in the past decade to the design of new protocols for the activation of N-hydroxy imides in the presence of nonmetal initiators. Herein we provide a concise overview of the most significant and successful examples in this field, with the final aim to furnish a useful instrument for all scientists actively involved in the O2-mediated selective oxidation of organic compounds and looking for environmentally safe alternatives to metal catalysis.

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Section: Reviewmentioning

confidence: 77%

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

Melone¹,

Punta²

2013

Beilstein J. Org. Chem.

151

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“…18,19 A radical mechanism is consistent with the formation of 47 by a process involving combination of a C-5 radical with oxygen that would give hydroperoxide A (Scheme 2). Precedent for peroxide formation and reductive cleavage in/by 20,21 Unique to B, however, is the potential for ring-opening to the R-ketoamide C, which can reclose in a complementary fashion to form the 2-thiohydantoin 47, with experimental support for this sequence of events obtained as follows. Snider has reported that radicals generated in the presence of Mn(OAc) 3 /Cu(OAc) 2 can undergo further oxidation in which the resulting cation is trapped by acetic acid.…”

Section: 15mentioning

confidence: 98%

Inhibitors of HCV NS5A: From Iminothiazolidinones to Symmetrical Stilbenes

Romine

Laurent

Leet

et al. 2011

ACS Med. Chem. Lett.

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ABSTRACT:The iminothiazolidinone BMS-858 (2) was identified as a specific inhibitor of HCV repli cation in a genotype 1b replicon assay via a high-throughput screening campaign. A more potent analogue, BMS-824 (18), was used in resistance mapping studies, which revealed that inhibitory activity was related to disrupting the function of the HCV nonstructural protein 5A. Despite the development of coherent and interpretable SAR, it was subsequently discovered that in DMSO 18 underwent an oxidation and structural rearrangement to afford the thiohydantoin 47, a compound with reduced HCV inhibitory activity. However, HPLC bioassay fractionation studies performed after incubation of 18 in assay media led to the identification of fractions containing a dimeric species 48 that exhibited potent antiviral activity. Excision of the key elements hypothesized to be responsible for antiviral activity based on SAR observations reduced 48 to a simplified, symmetrical, pharmacophore realized most effectively with the stilbene 55, a compound that demonstrated potent inhibition of HCV in a genotype 1b replicon with an EC 50 = 86 pM.

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“…This appealing metal-free protocol evolved into enantioselective iodolactonization by using chiral amides or esters. The catalytic asymmetric halogen lactonization, as an emerging area, also attracted a lot of attention in recent years [42–44]. …”

Section: Introductionmentioning

confidence: 99%

Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy

Liu¹,

Zheng²,

Liu³

et al. 2013

Beilstein J. Org. Chem.

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SummaryA “stop-and-flow” strategy was developed for the chemoselective dioxygenation of alkenes with a PIFA-initiated cyclization. This method is conceived for the desymmetrization of seco-diene, and a series of substituted 5-hydroxymethyl-γ-lactones were constructed after hydrolysis. This strategy also differentiates terminally substituted alkenes and constitutes a potentially novel synthetic approach for the efficient synthesis toward velbanamine.

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Metal‐Free, Aerobic Dioxygenation of Alkenes Using Hydroxamic Acids

Cited by 130 publications

References 36 publications

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

Inhibitors of HCV NS5A: From Iminothiazolidinones to Symmetrical Stilbenes

Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy

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