2018년 2월 10일 토요일

Masamune · Bergman's cyclization

Masamune · Bergman's cyclization

Masamune · Baguman's cycling(Masamune · Bergman manga,: Masamune-Bergman cyclization) occurs when it is heated in the presence of a suitable hydrogen donor. Masamune · Bergman reactionor Also called Masamune · Bergman's cyclization aromatization. It is the most famous and well studied in the cyclization aromatization reaction. The reaction product is a derivative.

This reaction is a thermal reaction or (200 ºC or more) to form short-lived and highly reactive species. It reacts with any hydrogen donor such as. The reaction product when quenched by is, and for methanol the reaction product is.

When the moiety is incorporated in a 10-membered ring hydrocarbon ring (eg, cyclodeca-3-ene-1,5-diene), the reaction increases by increasing the reactivity Even at lower temperatures below ºC it will proceed.

Have similar 10-membered rings and are shown to show. These compounds produce intermediates as described above, causing cleavage of single strands or duplexes. New drugs including such as using this property have also been developed.

It is also suggested that mechanisms work in the formation of certain species, such as those having chlorobenzene sites in their structure. In this mechanism, the halide salt donates halogen. Medium 37 Model reaction using cyclodeca-1,5-diyn-3-ene of enyne at ºC, as a hydrogen source as a halogen source, supports this theory.

This reaction is for enediyne, and it has been clarified that p - benzine formation is. Next, halide ions are converted to new Br- It is believed that two electrons are donated in the formation of the C bond and the radical electrons are passed through a temporary C1 - C4 bond to form an intermediate. This anion is a powerful base and extracts protons from DMSO to become the final product. No dibromide or dihalogen product () is formed.

footnote

1. *Darby, N .; Kim, CU; Salaun, JA; Shelton, KW; Takada, S .; Masamune, S. (1971). "Concerning the 1,5-didehydro [10] annulene system" . J. Chem. Soc. Chem. Commun. *23: 1516 - 1517.:. 2. *Richard R. Jones, Robert G. Bergman (1972). "P-Benzyne. Generation as an intermediate in a thermal isomerization reaction and trapping evidence for the 1,4-benzenediyl structure". __*94(2): 660-661.:. 3. *RK Mohamed, PW Peterson and IV Alabugin; Peterson; Alabugin (2013). "Concerned Reactions that Produce Diradicals and Zwitterions: Electronic, Steric, Conformational and Kinetic Control of Cycloaromatization Processes". Chem. Rev. *113(9): 7089 - 7129.:. 4. *Luca Banfi, Andrea Basso, Giuseppe Guanti, and Renata Riva (2006). __*HL - 1786 GR: 261-275. 5. *Charles L. Perrin, Betsy L. Rodgers, and Joseph M. O'Connor (2007). "Nucleophilic Addition to a p-Benzyne Derived from an Enediyne: A New Mechanism for Halide Incorporation into Biomolecules". __*129(15): 4795.:. 6. ****Stu Borman (2007). __ ..

External link

  • \ - Organic Chemistry Portal
  • \ - ODOOS - synthetic reaction database - by Chem-Station

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Post Date : 2018-02-10 20:30

This article is taken from the Japanese Wikipedia Masamune · Bergman's cyclization

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