Phosphine-Catalyzed Formal[6+2] Cycloadditions of α'-Methylene 2-Cyclopentenones
نویسندگان
چکیده
منابع مشابه
Synthesis of carbocyclic hydantocidins via regioselective and diastereoselective phosphine-catalyzed [3 + 2]-cycloadditions to 5-methylenehydantoins.
The phosphine-catalyzed [3 + 2]-cycloaddition of 5-methylenehydantoins 4 with the ylides 5, derived from addition of tributylphosphine to the 2-butynoic acid derivatives, 6a-d, gives spiro-heterocyclic products. The camphor sultam derivative 6b gives optically active products. Noteable was that the ylides derived from ethyl 2-butynoate and the 3-(2-butynoyl)-1,3-oxazolidin-2-one derivatives 6c ...
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The rearrangement of 1-ethynyl-2-propenyl pivaloates to cyclopentenones catalyzed by cationic triphenylphosphinegold(I) complexes is described. The reaction tolerates both alkyl and aryl substitution at the acetylenic and olefinic positions. Importantly, the gold(I)-catalyzed rearrangement of enantioenriched propargyl pivaloates proceeds with excellent chirality transfer, thus providing a pract...
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Phosphine-catalyzed [3+2]cycloaddition reactions of electron-deficient allenes and alkynes with a,b-unsaturated carbonyl compounds can give access to important highly functionalized cyclopentenes. The seminal example of such a transformation was first reported by Lu et al. in 1995, and its asymmetric version in 1997 by the group of Zhang. However, it took another ten years before the potential ...
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SYNLETT 2004, No. 6, pp 1054–105806.05.2004 Advanced online publication: 25.03.2004 DOI: 10.1055/s-2004-822895; Art ID: G04404ST © Georg Thieme Verlag Stuttgart · New York Abstract: Using only 10% of CrCl2 as catalyst, manganese-powder as reducing agent and TMSCl as scavenger, 2-methylene-a,w-dialdehydes and -ketones can be coupled to form cyclic diols diastereoselectively. The diastereomeric e...
متن کاملIridium-catalyzed intramolecular [4 + 2] cycloadditions of alkynyl halides
Iridium-catalyzed intramolecular [4 + 2] cycloadditions of diene-tethered alkynyl halides were investigated by using [IrCl(cod)](2) as catalyst, and dppe was found to be the most suitable phosphine ligand for the reaction. No oxidative insertion of the iridium into the carbon-halide bond was observed, and the reactions proceeded to provide the halogenated cycloadducts in good yield (75-94%). Th...
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ژورنال
عنوان ژورنال: Chinese Journal of Organic Chemistry
سال: 2019
ISSN: 0253-2786
DOI: 10.6023/cjoc201903061