Carbenoide Additionen an 3,6‐Dihydro‐4‐methyl‐2<i>H</i>‐pyran Bildung gespannter Oxatricycloheptane bei der Lithiierung des Dibromcarben‐Addukts

Jendralla, H.; Pflaumbaum, W.

doi:10.1002/cber.19821150120

Cited by 9 publications

(3 citation statements)

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“…However, no pathway from these to ethenediolate or cyclopropanetriolate compounds was found. Instead, calculations suggest that 5 and 6 are formed by very similar mechanisms to those proposed for the synthesis of f-block ethenediolate complexes (Figure , see SI for full reaction pathways). ,,, That is, the magnesium hydride dimers 3 and 4 react with one molecule of CO to give transient κ 2 -C,O-formyl complexes, e.g., VI (from 3 ), the C–O bonds of which insert into the Mg–H bond of magnesium hydride fragments, e.g., IV (from 3 ), to give bridged oxomethylene compounds, e.g., VIII (from 3 ). A second molecule of CO inserts into one Mg–C bond of the oxomethylene compounds, and subsequent 1,2-hydrogen migrations within the coordinated C 2 H 2 O 2 fragments occur to give the magnesium ethenediolate chelate complexes, 5 and 5 Dep .…”

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confidence: 82%

Activation of CO by Hydrogenated Magnesium(I) Dimers: Sterically Controlled Formation of Ethenediolate and Cyclopropanetriolate Complexes

et al. 2015

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This study details the formal hydrogenation of two magnesium(I) dimers {(Nacnac)Mg}2 (Nacnac = [{(C6H3R2-2,6)NCMe}2CH](-); R = Pr(i) ((Dip)Nacnac), Et ((Dep)Nacnac)) using 1,3-cyclohexadiene. These reactions afford the magnesium(II) hydride complexes, {(Nacnac)Mg(μ-H)}2. Their reactions with excess CO are sterically controlled and lead cleanly to different C-C coupled products, viz. the ethenediolate complex, ((Dip)Nacnac)Mg{κ(1)-O-[((Dip)Nacnac)Mg(κ(2)-O,O-O2C2H2)]}, and the first cyclopropanetriolate complex of any metal, cis-{((Dep)Nacnac)Mg}3{μ-C3(H3)O3}. Computational studies imply the CO activation processes proceed via very similar mechanisms to those previously reported for related reactions involving f-block metal hydride compounds. This work highlights the potential magnesium compounds hold for use in the "Fischer-Tropsch-like" transformation of CO/H2 mixtures to value added oxygenate products.

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confidence: 82%

Activation of CO by Hydrogenated Magnesium(I) Dimers: Sterically Controlled Formation of Ethenediolate and Cyclopropanetriolate Complexes

et al. 2015

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“…(1R,7S,8r)-methyl 3,5-dioxabicyclo[5.1.0]octane-8-carboxylate (18) 62 Rhodium acetate (250 mg, 0.57 mmol, 2.4 X 10 -3 equiv) was dissolved in 4,7-dihydro-1,3-dioxepine (240 g). To this was added a solution of methyl diazoacetate (240 g, 2.4 mol, 1.0 equiv) in 4,7-dihydro-1,3-dioxepine (350 g) at the rate of 1 drop per second (4 h total approximately).…”

Section: § Preparation Of Trans Cyclooctenes and Their Derivativesmentioning

confidence: 99%

“…Both the pure and semi-pure product were suitable for subsequent reactions. 62 (1R,7S,8r)-methyl 3,5-dioxabicyclo[5.1.0]octane-8-carboxylate (43 g, 0.25 mol, 1.00 equiv) was dissolved in THF (30 mL). To this solution water (30 mL) was added and the mixture was cooled in an ice bath.…”

Section: § Preparation Of Trans Cyclooctenes and Their Derivativesmentioning

confidence: 99%

Synthesis of strained ring systems for bioorthogonal labeling applications

Varga¹

2015

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and great number of corrections. I would also like to thank all the members of the "Lendület" Chemical Biology Research Group for their continuous help in practical matters. Furthermore I would like to thank my parents for their support. Special thanks is due to Kim Eunha and Krisztina Hegyi for the live cell imaging experiments, to Mihály Kállay for the computational data, to Szabolcs Béni for his assistance with the NMR experiments, Soma Vesztergom for the valuable discussions concerning kinetic measurements, and to the Szostak lab for the use of the stop flow system.

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Desaminative Erzeugung und Folgereaktionen von trans‐Tetra‐hydrooxepin‐Derivaten, den ersten heterocyclischen trans‐Cycloheptenen

Jendralla

1982

Chem. Ber.

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Deaminative Generation and Reactions of trans-Tetrahydrooxepin Derivatives, the First Heterocyclic trans-CycloheptenesDeamination of N-(6-methyl-3-oxabicyclo[4.1.0]hept-exo-7-yl)-N-nitrosourea (1) in weakly alkaline methanol produced 5-methoxy-5-methyl-3(E)-tetrahydrooxepin (8) and 3-methoxy-5-methyl-4(E)-tetrahydrooxepin (9) besides minor amounts of exo-7-methoxy-6-methyl-3-oxabicyclo[4.1 .O]heptane (10). The methoxy group is incorporated stereospecifically. In the presence of 2,3-dimethyl-1,3-butadiene 8 and 9 are trapped as the Diels-Alder adducts 14 and 16. At ambient temperature 8 and 9 suffer isomerization to the corresponding (Z)-tetrahydrooxepins 13 and 17 and, to a little extent, dimerization in an ene-type reaction to two diastereomers with the constitution 15. Under strongly alkaline conditions 10 is the main product of the deamination of 1; tetrahydrooxepins being formed only in traces. Under these conditions endo-7-methoxy-6-methyl-3-oxabicyclo[4.1 .O]heptane (11) and 7-methyl-4-oxatricycl0[3.2.0.0~~~]heptane (12) are produced, additionally. The change in the product composition points to a transition of the cationic decomposition mechanism under weakly alkaline conditions to a carbene mechanism under strongly alkaline conditions. Die basische Desaminierung bicyclischer Cyclopropylnitrosoharnstoffe ist eine erfolgreiche Methode zur Erzeugung von trans-Cyclohepten-und cis, trans-Cycloheptadien-Derivaten'). Sie versagt jedoch, wenn der Bicyclus Sauerstoffatome aufweist, die mit dem Cyclopropanring in Chem. Ber. //5(1982)

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Carbenoide Additionen an 3,6‐Dihydro‐4‐methyl‐2H‐pyran Bildung gespannter Oxatricycloheptane bei der Lithiierung des Dibromcarben‐Addukts

Cited by 9 publications

References 13 publications

Activation of CO by Hydrogenated Magnesium(I) Dimers: Sterically Controlled Formation of Ethenediolate and Cyclopropanetriolate Complexes

Activation of CO by Hydrogenated Magnesium(I) Dimers: Sterically Controlled Formation of Ethenediolate and Cyclopropanetriolate Complexes

Synthesis of strained ring systems for bioorthogonal labeling applications

Desaminative Erzeugung und Folgereaktionen von trans‐Tetra‐hydrooxepin‐Derivaten, den ersten heterocyclischen trans‐Cycloheptenen

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