- A cobalt-phosphine complex as mediator in the formation of carbon-carbon bonds
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The tetrakis(trimethylphospine)cobalt(0) complex, [Co{P(CH3)3}4], in either stoichiometric or catalytic amounts, was shown to be an efficient mediator for a one-pot Reformatsky-type reaction between activated halogen derivatives (esters, amides, lactones) and carbonyl compounds (aldehydes, ketones) to produce a variety of alcohols.
- Orsini,Pelizzoni,Pulici
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- Reduction of Substituted Δ2-Isoxazolines. Synthesis of β-Hydroxy Acid Derivatives
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Three separate methods are reported for the formation of β-hydroxy acid derivatives from readily available substituted Δ2-isoxazolines.Cycloaddition of 2,2-dimethylpropanenitrile oxide with a variety of olefins followed by reductive cleavage produces α '-tert-butyl β-hydroxy ketones.These are cleaved to β-hydroxy tert-butyl esters by Baeyer-Villiger oxidation with peroxytrifluoroacetic acid.In the second approach, α ',β-dihydroxy ketones are generated via cycloaddition of olefins with the nitrile oxide generated from 2--2-methyl-1-nitropropane followed by reductive ring opening.Standard periodic acid cleavage gives β-hydroxy acids.Finally, 3-methoxy-substituted Δ2-isoxazolines, readily available via benzenesulfonylcarbonitrile oxide-olefin cycloaddition and methoxide displacement, are directly reduced to β-hydroxy esters.
- Curran, Dennis P.,Scanga, Susan A.,Fenk, Christopher J.
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p. 3474 - 3478
(2007/10/02)
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