Oxygen-atom transfer from iodosobenzene to ketenes, .alpha.-keto carboxylic acids, and ketones

Moriarty, Robert M.; Gupta, Satish C.; Hu, Henry; BERENSCHOT, D. R.; White, Kenneth B.

doi:10.1021/ja00393a040

Cited by 98 publications

(17 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With a threefold excess of HOF·CH 3 CN, 5 was converted into 6 in a single step. Similarly, 2-cyclopentylidenecyclopetanone (7) and tetracyanoethylene (8) have been epoxidized in the past, the first by treating it with DMDO for 24 h, [7] and the second by Scheme 1 peracids or iodosobenzene, again with prolonged reaction times. [8] We treated both 7 and 8 with HOF·CH 3 CN and obtained the respective epoxides 9 and 10 in less than 3 min with yields higher than 90% (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

The First, General, Highly Efficient Method for Preparing Tetrasubstituted Epoxides Using HOF·CH₃CN

Rozen

Golan

2003

Eur J Org Chem

View full text Add to dashboard Cite

Tetrasubstituted epoxides, and especially electron‐depleted ones, generally are difficult to prepare. HOF·CH3CN complex, probably the best oxygen transfer agent known today, epoxidizes tetrasubstituted alkenes at 0 °C in a matter of minutes or less in excellent yields. HOF·CH3CN complex is very easy to prepare by bubbling diluted fluorine (commercial) through aqueous acetonitrile. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

show abstract

Section: Resultsmentioning

confidence: 99%

The First, General, Highly Efficient Method for Preparing Tetrasubstituted Epoxides Using HOF·CH₃CN

Rozen

Golan

2003

Eur J Org Chem

View full text Add to dashboard Cite

show abstract

“…Specifically, (2 S ,3 S )‐ 5 was subjected to a conventional three‐step protection/oxidation sequence to provide the aldehyde 9 in good yield. With respect to ( R )‐ 8 , after hydrogenolysis of the benzyl ester, conversion of the resulting keto acid into ketophosphonate 10 was effected by a one‐pot procedure, which involved excision of the carboxylate by iodosobenzene‐promoted oxidative decarboxylation,15 formation of the ethyl chloroformate derived mixed anhydride, and addition of lithio dimethylmethanephosphonate.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of (−)‐Octalactin A by a Strategic Vanadium‐Catalyzed Oxidative Kinetic Resolution

et al. 2008

View full text Add to dashboard Cite

The kinetic resolution of racemic material is a well-established approach used to prepare a wide range of enantiomerically enriched compounds.[1] However, the overall efficiency of a standard kinetic resolution is limited to a maximum theoretical yield of 50 % of the enriched chiron, with the balance of undesired material being discarded in most applications.[2] As a result of this inherent overall efficiency, [3] kinetic resolution is often deemed unacceptable on a preparative scale except for the most simple and inexpensive of substrates. Consequently, kinetic resolution methods, especially in the context of complex molecule synthesis, have largely been relegated to the preparation of small chiral building blocks at an early stage of the synthesis.Having recently developed a vanadium-catalyzed asymmetric aerobic oxidation of a hydroxycarbonyl compounds, [4] we became interested in exploring the potential of this kinetic resolution methodology, to move beyond the preparation of simple building blocks toward a more meaningful, strategic synthetic function. The observation that asymmetric oxidation of substrates bearing multiple stereocenters by catalytic amounts of [VO(OiPr) 3 ] and (S)-2-(3,5-di-tert-butylsalicylideneamino)-tert-butyl-1-ethanol (1) resulted in the isolation of both enantioenriched alcohol and ketone products motivated us to consider a synthetic strategy (Figure 1) wherein both components of the resolution might be leveraged toward a single synthetic target. By doing so, the kinetic resolution serves as the key structural and stereochemical branching point in the synthetic sequence and the overall efficiency of the resolution is improved beyond 50 %. Herein, we report the successful implementation of this type of resolution/ recombination synthetic strategy [5] to the total synthesis of the bioactive marine metabolite octalactin A. [6] Octalactin A (2) belongs to a small class of medium-ring lactones isolated from marine microorganisms. In vitro bioassays have shown octalactin A to possess significant cytotoxicity toward B-16-F10 murine melanoma and HCT-116 human colon tumor cell lines. [6,7] As a result, numerous synthetic investigations, including several total syntheses, [8] have been directed towards its preparation.[9] Our approach to octalactin A begins in an antithetic sense with disconnection of the C10-C15 side chain and retrolactonization of the eight-membered core, thus leading to the simplified fragments 3 and 4 (Scheme 1). From here, the basis of our strategy stems from the identification of an element of pseudosymmetry in the seco-acid component 3. Specifically, we envisioned that the repeating anti-1,2-vic-hydroxymethyl stereodiad could be derived from the enantiomers of racemic anti-1,2-vic-hydroxymethyl stereoconstruct (AE )-5. As such, oxidative resolution of (AE )-5 and subsequent head-to-tail recombination of elaborated fragments would allow rapid access to 3. The C10-C15 side chain 4 could be obtained by asymmetric addition of an isopropyl group to a suitably functional...

show abstract

“…Ketenes are fascinating monomers because their polymerizations can create various oxygen‐containing polymers such as polyesters, polyethers, and polyketones 1–3. The anionic polymerization of ketenes has been especially reported to afford the corresponding polyesters selectively 4–8.…”

Section: Introductionmentioning

confidence: 99%

Application of ketenes to well‐defined polyester synthesis. III. Living anionic polymerization of ethyl(4‐methoxyphenyl)ketene—Development of polyester having masked phenol side chain

Sudo

Uchino

Endō

2001

J. Polym. Sci. A Polym. Chem.

View full text Add to dashboard Cite

A novel ketene, ethyl(4-methoxyphenyl)ketene (EMPK), was synthesized by the dehydrochlorination of 2-(4-methoxyphenyl)butanoyl chloride. The anionic polymerizations of EMPK by butyllithium in tetrahydrofuran at Ϫ20°C were carried out with a varying feed ratio to give the corresponding polyesters having predictable molecular weights and narrow molecular weight distributions, quantitatively. The selective formation of the polyester was confirmed by IR analysis, and the reductive degradation of the polymer was supported by lithium-aluminium hydride. The second feed of the monomer (after the first stage of polymerization) resulted in the formation of the polymer with the expectedly increased molecular weight and low polydispersity to strongly support the living mechanism of this polymerization.

show abstract

Oxygen-atom transfer from iodosobenzene to ketenes, .alpha.-keto carboxylic acids, and ketones

Cited by 98 publications

References 1 publication

The First, General, Highly Efficient Method for Preparing Tetrasubstituted Epoxides Using HOF·CH₃CN

The First, General, Highly Efficient Method for Preparing Tetrasubstituted Epoxides Using HOF·CH₃CN

Synthesis of (−)‐Octalactin A by a Strategic Vanadium‐Catalyzed Oxidative Kinetic Resolution

Application of ketenes to well‐defined polyester synthesis. III. Living anionic polymerization of ethyl(4‐methoxyphenyl)ketene—Development of polyester having masked phenol side chain

Contact Info

Product

Resources

About

Oxygen-atom transfer from iodosobenzene to ketenes, .alpha.-keto carboxylic acids, and ketones

Cited by 98 publications

References 1 publication

The First, General, Highly Efficient Method for Preparing Tetrasubstituted Epoxides Using HOF·CH3CN

The First, General, Highly Efficient Method for Preparing Tetrasubstituted Epoxides Using HOF·CH3CN

Synthesis of (−)‐Octalactin A by a Strategic Vanadium‐Catalyzed Oxidative Kinetic Resolution

Application of ketenes to well‐defined polyester synthesis. III. Living anionic polymerization of ethyl(4‐methoxyphenyl)ketene—Development of polyester having masked phenol side chain

Contact Info

Product

Resources

About

The First, General, Highly Efficient Method for Preparing Tetrasubstituted Epoxides Using HOF·CH₃CN

The First, General, Highly Efficient Method for Preparing Tetrasubstituted Epoxides Using HOF·CH₃CN