نتایج جستجو برای: cyclizations

تعداد نتایج: 570  

Journal: :Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan 2012
Hiroyuki Ishibashi

This review deals with the synthesis of alkaloids using radical cyclizations. Emphasis has been placed on radical cascades that provide synthesis of (-)-cephalotaxine, (±)-stemonamide, and (±)-isostemonamide.

Journal: :Chemical communications 2009
Huimin Zhai Maria Zlotorzynska Glenn Sammis

Nitrogen-centered radical cyclizations onto silyl enol ethers were utilized for the syntheses of protected polyhydroxylated pyrrolidines 2-hydroxymethyl-3-hydroxypyrrolidine and 1,4-dideoxy-1,4-imino-L-ribitol.

Journal: :Pure and Applied Chemistry 1992

Journal: :Organic letters 2010
Roman Shchepin Chunping Xu Patrick Dussault

B(C(6)F(5))(3) promotes regio- and stereoselective cyclizations of unsaturated alkoxysilanes to generate oxasilinanes and oxasilepanes. The same products are available directly from alkenols via tandem silylation and hydrosilylation.

Journal: :Chemical science 2015
Alan R Burns Amaël G E Madec Darryl W Low Iain D Roy Hon Wai Lam

2,2-Disubstituted cyclic 1,3-diketones containing a tethered electron-deficient alkene undergo chiral phosphoric acid-catalyzed desymmetrizing Michael cyclizations to give bridged bicyclic products in high enantioselectivities. Both bicyclo[3.2.1]octanes and bicyclo[3.3.1]nonanes are accessible using this methodology.

Journal: :Chemical and Pharmaceutical Bulletin 1991

Journal: :Organic & biomolecular chemistry 2011
Christopher B DeZutter John H Horner Martin Newcomb

The 1-hydroxy-1-methyl-6,6-diphenyl-5-hexenyl radical (4a) and the 1-hydroxy-1-methyl-7,7-diphenyl-6-heptenyl radical (4b) were prepared from the corresponding PTOC esters (anhydrides of a carboxylic acid and N-hydroxypyridine-2-thione). The key step in the synthetic method for the precursors was a coupling reaction of the respective carboxylic acids with the thiohydroxamic acid, which was cond...

Journal: :Molecules 2004
Tim Dreessen Christian Jargstorff Lars Lietzau Christian Plath Arne Stademann Uta Wille

The recently discovered novel concept of self-terminating, oxidative radical cyclizations, through which alkynes can be converted into carbonyl compounds under very mild reaction conditions using O-centered inorganic and organic radicals as oxidants, is described.

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