A Facile Route to Bulladecin-Type Acetogenins - Total Synthesis of Asimilobinand Correction of the Configuration of Its Tetrahydrofuran Segment

Wang, Zhimin; Tian, Shi‐Kai; Shi, Min

doi:10.1002/(sici)1099-0690(200001)2000:2<349::aid-ejoc349>3.0.co;2-j

Cited by 31 publications

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References 36 publications

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“…All the desired products were produced in good to excellent yields (Scheme 5.33). Reaction Procedure (Scheme 5.33): In a glove-box, vials equipped with Teflon-coated magnetic stirrer bars were charged with Co 2 (CO) 8 , the appropriate dihydrooxazine and toluene. The vials were then placed in a custom-made six-well high-pressure reactor which was subsequently closed, removed from the glove-box and pressurized with carbon monoxide (500 psi partial pressure) and hydrogen (500 psi partial pressure).…”

Section: Six-membered and Other Heterocyclesmentioning

confidence: 97%

“…Notably, this type of cyclization was applied in the total synthesis of gigantetrocin A and asimilobin by Shi and co-workers. [6][7][8] More recently, the oxidative cyclization of alkenols and alkenes/alkynes was reported (Scheme 5.3). 9 In detail, the aerobic oxidation of alkyl-and phenyl-substituted 4-pentenols (bishomoallyl alcohols), catalyzed by cobalt(II) complexes in solutions of g-terpinene or cyclohexa-1,4-diene, stereoselectively gave tetrahydrofurylmethyl radicals.…”

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CHAPTER 5. Cobalt-Catalyzed Heterocycle Synthesis

2014

Catalysis Series

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Cobalt has the chemical configuration [Ar]4s 2 3d 7 and has oxidation states Co(II) and Co(III). Cobalt has many applications in a wide range of areas. In materials, cobalt is primarily used as the metal, for example, in the preparation of magnetic, wear-resistant and high-strength alloys. In biology, cobalt is the active center of coenzymes called cobalamins, the most common example of which is vitamin B 12 . As such, it is an essential trace dietary mineral for all animals. Cobalt in inorganic form is also an active nutrient for bacteria, algae and fungi. In chemistry, various cobalt compounds are used as oxidation catalysts in chemical reactions. Cobalt acetate is used for the conversion of xylene to terephthalic acid, the precursor to the bulk polymer poly(ethylene terephthalate). Typical catalysts are the cobalt carboxylates (known as cobalt soaps). They are also used in paints, varnishes and inks as 'drying agents' through the oxidation of drying oils. The same carboxylates are also used to improve the adhesion of steel to rubber in steel-belted radial tires. Cobalt-based catalysts are also important in reactions involving carbon monoxide. In this chapter, the applications of cobalt catalysts in the synthesis of heterocycles is discussed. Five-Membered HeterocyclesIn 1986, Pattenden and co-workers reported a cobalt-promoted oxidative freeradical cyclization of alkyl bromides, 1 by which functionalized butyrolactones were selectively formed in good yields. In 1990, a convenient method for the stereoselective preparation of trans-2-hydroxymethyltetrahydrofurans by the oxidative cyclization of 5-hydroxy-1-alkenes was developed by Inoki and Mukaiyama. 2 They used bis(1-morpholinocarbamoyl-4,4-dimethyl-1,3-pentanedionato)cobalt(II) [Co(modp) 2 ] as the catalyst with molecular oxygen as the RSC Catalysis Series No.

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Section: Six-membered and Other Heterocyclesmentioning

confidence: 97%

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confidence: 99%

CHAPTER 5. Cobalt-Catalyzed Heterocycle Synthesis

2014

Catalysis Series

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“…It has originally been isolated from the seeds of Asimina triloba [118] but has also been found in extracts of the bark of Goniothalamus giganteus (Annonaceae) [119] by McLaughlin and co-workers [120–121]. In 1999, Wang and Shi et al .…”

Section: Reviewmentioning

confidence: 99%

“…In 1999, Wang and Shi et al . disclosed the first total synthesis of (–)-asimilobin ( 74 ) and its diastereomer using a highly efficient and stereocontrolled synthetic strategy to construct the desired bis-THF ring building block 73 in two steps (Scheme 15) [120–121]. Thus, starting from commercially available trans -1,5,9-decatriene ( 71 ) a stereo- and positionselective Sharpless AD reaction [86–88] provided C 2 -symmetric diol 72 (R = H) in high selectivity (ee >94%).…”

Section: Reviewmentioning

confidence: 99%

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The direct oxidative diene cyclization and related reactions in natural product synthesis

Adrian¹,

Gross²,

Stark³

2016

Beilstein J. Org. Chem.

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SummaryThe direct oxidative cyclization of 1,5-dienes is a valuable synthetic method for the (dia)stereoselective preparation of substituted tetrahydrofurans. Closely related reactions start from 5,6-dihydroxy or 5-hydroxyalkenes to generate similar products in a mechanistically analogous manner. After a brief overview on the history of this group of transformations and a survey on mechanistic and stereochemical aspects, this review article provides a summary on applications in natural product synthesis. Moreover, current limitations and future directions in this area of chemistry are discussed.

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Asymmetric Dihydroxylation of Alkenes

2005

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The oxidation of alkenes to vicinal diols using osmium tetroxide is one of the most selective and reliable transformations in organic synthesis. The reaction stereospecifically produces a cis‐1,2‐glycol and is tolerant of a wide array of functional groups. Methods have been developed to oxidize alkenes stoichiometrically, as well as in the presence of catalytic amounts of osmium tetroxide, when a suitable secondary oxidant is present. The latter process is particularly useful considering the expense and toxicity of osmium tetroxide. The utility of dihydroxylation in organic synthesis is enhanced by the facile transformations of the cis‐1,2‐diol products into other useful derivatives. Among the most versatile intermediates are the corresponding cyclic sulfates, which serve as reactive epoxide equivalents that can be used singly or doubly displaced with amine‐, oxygen‐, sulfur‐, or carbon‐based nucleophiles. The reaction of osmium tetroxide with alkenes is accelerated by several orders of magnitude in the presence of coordinating amine ligands such as triethylamine, quinuclidine, or diazobicyclooctane. The logical extension to asymmetric osmylation of alkenes in the presence of chiral amine bases spurred the study of asymmetric dihydroxylation. The breakthrough of catalytic turnover in the cinchona alkaloid‐osmium tetroxide system revolutionized the field of asymmetric dihydroxylation. Specialized ligands have been developed to provide position selectivity in the dihydroxylation of polyenes, efficient kinetic resolution of racemic substrates, and high levels of enantioselectivity for each of six alkene classes.

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A Facile Route to Bulladecin-Type Acetogenins - Total Synthesis of Asimilobinand Correction of the Configuration of Its Tetrahydrofuran Segment

Cited by 31 publications

References 36 publications

CHAPTER 5. Cobalt-Catalyzed Heterocycle Synthesis

CHAPTER 5. Cobalt-Catalyzed Heterocycle Synthesis

The direct oxidative diene cyclization and related reactions in natural product synthesis

Asymmetric Dihydroxylation of Alkenes

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