The preparation and chemistry of α-nitroepoxides

Newman, Howard; Angier, Robert B.

doi:10.1016/s0040-4020(01)97880-9

Cited by 66 publications

(31 citation statements)

References 22 publications

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“…It should be noted that similar ring-opening reactions with a-nitro-or chloro-substituted epoxides have been reported, and in those cases, both nitro and chlorine act as leaving groups during the acid-mediated ring-opening process. [15][16][17] In summary, we have demonstrated an efficient Ocyclization reaction between a-fluorosulfoximines and Table 3. Survey of ring opening reaction conditions.…”

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confidence: 78%

Efficient Synthesis and Ring‐Opening Reactions of Monofluorinated Epoxides Derived from α‐Fluorosulfoximines

Zhang

2010

Adv Synth Catal

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Monofluorinated epoxides were successfully prepared through the O-cyclization reaction between a-fluorosulfoximines and ketones. The obtained fluoroepoxides were found to readily undergo an interesting ring-opening process (involving both a C À F bond cleavage and another C À F bond formation) in the presence of titanium tetrafluoride or pyridinium poly(hydrogen fluoride) to afford afluorinated ketones. The later process constitutes a formal catalytic 1,2-fluorine shift reaction.Keywords: epoxides; fluorine; fluorine shift; ringopening; sulfoximines Due to the high electronegativity and small size of the fluorine atom, the replacement of hydrogen atom(s) by fluorine in organic compounds often results in a profound change in their physical, chemical and biological properties.[1] As a consequence, over the past decade, organofluorine compounds have found broad applications in both life sciences and materials science.[2] To date, many endeavours have been made to develop new efficient synthetic methods for the selective introduction of fluorine atom(s) or fluorinated moieties into organic molecules.[2] Although epoxides are highly useful building blocks in organic synthesis, the reports on the preparation and synthetic utilizations of monofluorinated epoxides are scarce. [3][4][5] Monofluorinated epoxides are usually prepared by the epoxidation of monofluoroolefins, [3] the treatment of fluorohalohydrins with a base, [4] or the Darzens reaction between a ketone and dibromo(tertbutyldimethylsililyl)fluoromethane [5] (or ethyl dibromofluoroacetate [6] ). Fluorinated epoxides are known to be relatively unstable, and tend to undergo a variety of ring-opening reactions with nucleophiles.[3c,7,9] When monofluoroepoxides were treated with fluoride ion, a-fluorinated carbonyl compounds were obtained through a ringopening process involving both a C À F bond cleavage and another C À F bond formation. [3a,8] This type of transformation also proceeded smoothly in the presence of triethylamine-tris(hydrogen fluoride) [9] or boron trifluoride [10] . Futhermore, the acid-catalyzed isomerizations of polyfluorinated epoxides into the corresponding ketones have been previously documented. [7] As part of our efforts to develop new synthetic approaches for organofluorine compounds, [11] we recently developed some unique synthetic methods for the preparation of di-and monofluorinated compounds by using fluorinated sulfoximine reagents. [12,13] In particular, the a-difluoromethylsulfoximine was used as a novel and efficient difluorocarbene reagent, [12] and the a-fluorosulfoximines could readily react with simple nitrones to give monofluoroalkenes with excellent Z/E stereocontrol. [13] In this paper, we wish to report another interesting synthetic application of fluorinated sulfoximines, that is, the efficient synthesis of a-monofluorinated epoxides derived from a-fluorosulfoximines and ketones, and the subsequent ringopening reaction of the monofluoroepoxides by using TiF 4 or pyridinium poly(hydrogen fluoride) (Olahs reage...

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confidence: 78%

Efficient Synthesis and Ring‐Opening Reactions of Monofluorinated Epoxides Derived from α‐Fluorosulfoximines

Zhang

2010

Adv Synth Catal

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“…89 This unusual transformation is probably caused by the electrophilic centre of the oxidising a-Nitroepoxides 190 can be obtained from conjugated nitroalkenes using hydrogen peroxide in basic conditions. 90 Nucleophilic ring opening of these epoxides usually leads to the a-hydroxy nitro intermediates 191 that are prone to a fast hydrolysis to the parent carbonyl compound 192 (Scheme 52).…”

Section: Oxidative Methodsmentioning

confidence: 99%

Recent synthetic developments in the nitro to carbonyl conversion (Nef reaction)

2004

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“…The isoprenoid dicarbonyl compounds 1 and 2 were synthesized according to the method outlined in Scheme 1 for compound 2, based on procedures in the literature for analogous compounds (step a, [33] b, [34] c, [35] d, [36] e, [36] f, [37] g, [38] , and h [39] ) and described in detail below, beginning with the preparation of 16. Compound 3 was prepared from (±)-camphorsulfonic acid by formation of the sulfonyl chloride, conversion to the sulfonamide, and oxidation to the camphorquinone by analogy to a literature procedure [40] for camphorquinonesulfonamides of α-amino acids, as described in detail below.…”

Section: Synthetic Strategymentioning

confidence: 99%

Inactivation of Protein Farnesyltransferase by Active-Site-Targeted Dicarbonyl Compounds

Okolotowicz

Lee

Hartman

et al. 2001

Arch. Pharm. Pharm. Med. Chem.

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The preparation and chemistry of α-nitroepoxides

Cited by 66 publications

References 22 publications

Efficient Synthesis and Ring‐Opening Reactions of Monofluorinated Epoxides Derived from α‐Fluorosulfoximines

Efficient Synthesis and Ring‐Opening Reactions of Monofluorinated Epoxides Derived from α‐Fluorosulfoximines

Recent synthetic developments in the nitro to carbonyl conversion (Nef reaction)

Inactivation of Protein Farnesyltransferase by Active-Site-Targeted Dicarbonyl Compounds

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