Preparation of .pi.-allyl metal complexes by direct reaction of highly reactive transition metal powders with allylic halides

Rieke, Reuben D.; Kavaliunas, Arunas V.; Rhyne, Lee D.; Fraser, Dylan J.

doi:10.1021/ja00495a055

Cited by 45 publications

(4 citation statements)

References 3 publications

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“…It must be pointed out, however, that for the reduction of transition metal halides in the absence of phosphines, the reduction using lithium and naphthalene is far superior to reductions using potassium with regard to reactivity of the resulting metal powders. 23 Palladium Compounds. Palladium slurries react with a variety of aryl halides and result in frans-[P-(C2H5)3]2Pd(R)X compounds.…”

Section: Discussionmentioning

confidence: 99%

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Preparation of highly reactive metal powders. Preparation and reactions of highly reactive palladium and platinum metal slurries

Rieke¹,

Kavaliunas²

1979

J. Org. Chem.

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apparatus and the distillate was examined by analytical GC °C depending on sample) and TLC (30% ether/ petroleum ether). Ketol 7, when present, appeared at a longer retention time and a smaller R¡ than enone 6. The product yields and physical data are recorded in Tables I and II. In some instances analytical samples were obtained by preparative GC or TLC.Method B. To a solution of 4 mmol of alcohol 4 in 6 mL of dry pyridine was added 2 mmol of phosphorus oxychloride, and the solution was refluxed under nitrogen for 2.5 h. The reaction mixture was cooled, 15 mL of water was added, and the cloudy mixture was extracted three times with ether (total volume ~100 mL). The combined organic phases were extracted with cold 6 N HC1 until all the pyridine was removed. The ether solution was transferred to a round-bottomed flask, 20 mL of 2 N HC1 was added, and the two-phase system was vigorously stirred at room temperature for 18 h to effect hydrolysis of the enol ether moiety. The aqueous phase was separated and extracted three times with ether, and the combined organic phases were extracted once with saturated NaHC03 solution and once with brine and then dried. After removal of the solvent, the residue was distilled with a Kugelrohr apparatus and analyzed by GC and TLC. Generally a small amount of unhydrolyzed diene 5 was detected and was found to have a shorter retention time and a larger Rf than those for enone 6.10 The yields of enone 6 for this procedure are reported in Table I.Conversion of 4 to Ketol 7. A solution of 4-5 mmol of crude Grignard product 4 in 100 mL of ether was stirred vigorously for 18 h with 25 mL of 5% H2S04. After the aqueous phase was extracted three times with ether, the combined organic phases were extracted once with a saturated NaHCOg solution and once with brine and then dried with anhydrous MgS04. Removal of the solvent yielded ketol 7 which exhibited carbonyl absorption at 1720 cm"1 in its IR spectrum and a singlet methyl carbinol resonance at 8 1.3 in its NMR spectrum.Acknowledgments. The authors acknowledge the financial assistance of the National Research Council of Canada.

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Section: Discussionmentioning

confidence: 99%

“…This suggests that at elevated temperatures trans-[P(C2H5)3]2Pd(C6H5)I undergoes a reductive elimination reaction of the type observed for analogous nickel compounds. 23 The palladium compounds are stable in the solid state and in solution, although exhibiting some photodecomposition which appears to be accelerated by impurities.…”

Section: Discussionmentioning

confidence: 99%

Preparation of highly reactive metal powders. Preparation and reactions of highly reactive palladium and platinum metal slurries

Rieke¹,

Kavaliunas²

1979

J. Org. Chem.

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“…One powerful methodology along these lines is the reductive coupling of alkyl, allylic, and benzylic halides. Beginning in the 1940s, first-row transition metals including nickel tetracarbonyl were first used to form C sp3 –C sp3 bonds by the homocoupling of allylic halides. , The general propensity of first-row transition metals to engage in single electron chemistry has led to the discovery of variants of this reaction using not only Ni, but Ti, − V, Cr, Fe, − Mn, Co, − and Cu. , …”

Section: Reductive Halide Couplingmentioning

confidence: 99%

“…The first published report of cobalt-mediated allylic halide coupling was in 1979 by Rieke and co-workers, who stated that “Cobalt metal reacts with allyl bromide to yield 1,5-hexadiene without any evidence of an organocobalt compound.” In the early 1980s, Momose and co-workers subsequently discovered that chlorotris(triphenylphosphine)cobalt(I) was an effective reagent for coupling benzylic halides to form C sp3 –C sp3 bonds, including the synthesis of vicinal quaternary centers (Scheme ). Further exploration of the reactivity of this complex resulted in the reductive coupling of allyl halides and the transformation of bromohydrins to ketones. ,, Since Momose’s discovery of these cobalt-mediated transformations, the solid, air-stable CoCl(PPh 3 ) 3 has essentially supplanted the volatile and toxic Ni(CO) 4 as the reagent of choice for the reductive coupling of tertiary halides.…”

Section: Reductive Halide Couplingmentioning

confidence: 99%

Methods Utilizing First-Row Transition Metals in Natural Product Total Synthesis

2017

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First-row transition-metal-mediated reactions constitute an important and growing area of research due to the low cost, low toxicity, and exceptional synthetic versatility of these metals. Currently, there is considerable effort to replace existing precious-metal-catalyzed reactions with first-row analogs. More importantly, there are a plethora of unique transformations mediated by first-row metals, which have no classical second- or third-row counterpart. Herein, the application of first-row metal-mediated methods to the total synthesis of natural products is discussed. This Review is intended to highlight strategic uses of these metals to realize efficient syntheses and highlight the future potential of these reagents and catalysts in organic synthesis.

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Nickel(II) Chloride

Luh

Hsieh

2001

Encyclopedia of Reagents for Organic Synthesis

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Preparation of .pi.-allyl metal complexes by direct reaction of highly reactive transition metal powders with allylic halides

Cited by 45 publications

References 3 publications

Preparation of highly reactive metal powders. Preparation and reactions of highly reactive palladium and platinum metal slurries

Preparation of highly reactive metal powders. Preparation and reactions of highly reactive palladium and platinum metal slurries

Methods Utilizing First-Row Transition Metals in Natural Product Total Synthesis

Nickel(II) Chloride

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