Dipole-stabilized carbanions from thioesters. Evidence for stabilization by the carbonyl group

Reitz, David B.; Beak, Peter; Farney, Robert F.; Helmick, Larry S.

doi:10.1021/ja00485a030

Cited by 24 publications

(4 citation statements)

References 24 publications

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“…Only distinct signals were listed; GCMS (EI) m / z (rel intnesity) 372 (M + , 100), 284 (11), 268 (9), 147 (68), 73 (75); HRMS (EI) calcd for C 20 H 28 OSSi 2 (M + ) 372.1399, found 372.1423. The structure of 4i was further verified by hydrolysis with TFA (2 equiv) to thiobenzoin, the spectral data of which are consistent with literature data …”

Section: Methodssupporting

confidence: 87%

1,4-Silatropy of S-α-Silylbenzyl Thioesters: A Convenient Route to Silyl Enol and Dienol Ethers Accompanied by C−C Bond Formation via Thiocarbonyl Ylides

et al. 2003

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A novel convenient method for the generation of thiocarbonyl ylides from readily accessible starting materials and the first synthetic application of in situ generated ylides in the synthesis of silyl enol and dienol ethers, accompanied by C-C bond formation, is described. Under completely neutral conditions without any catalyst or additive, thermal reactions of S-alpha-silylbenzyl thioesters in sealed tubes at 180 degrees C provided silyl enol and dienol ethers in good to excellent yields with high stereoselectivities. This procedure consists of a multistep reaction in a one-pot process, i.e., 1,4-silatropy of S-alpha-silylbenzyl thioesters to give thiocarbonyl ylides, 1,3-electrocyclization of the ylides to give thiiranes, and the extrusion of sulfur from thiiranes to give silyl enol and dienol ethers.

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Section: Methodssupporting

confidence: 87%

1,4-Silatropy of S-α-Silylbenzyl Thioesters: A Convenient Route to Silyl Enol and Dienol Ethers Accompanied by C−C Bond Formation via Thiocarbonyl Ylides

et al. 2003

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“…Although it is possible that some dipole stabilization is provided by the vinylogous ester function in the intermediate 83 in the cyclizations of 84 to the benzofuran 85,98 the possibility that R = H, CH3 stabilization be delocalization into the phenyl ring is the dominant factor cannot be discounted. The nature of the stabilization of the intermediates 86 involved in the self-condensations of benzyl benzoate, allyl benzoate, and vinyl benzoate is similarly am- value of the reaction as well as the interesting idea that the intermediate could be cyclized to a novel 6 dioxane aromatic system has been discussed by Olofson,Lotts,and Barber.100 The first case of metalation of an unactivated ester adjacent to the acyl oxygen has been recently reported.2 The reaction of methyl 2,4,6-triisopropylbenzoate (3) with sec-butyllithium/ tetramethylethylenediamine (TMEDA) at -78 and -95 °C gives the organolithium 90 which can be trapped in acceptable yields as indicated in Scheme VIII. An interesting feature of this system is that a primary alcohol derivative also undergoes metalation.…”

Section: Oxygenmentioning

confidence: 97%

Dipole-stabilized carbanions: novel and useful intermediates

Beak¹,

Reitz²

1978

Chem. Rev.

Self Cite

218

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“…Phosphorochloridites were prepared easily in one step from the corresponding binaphthols 11. Intermediate compound ( S )‐2‐(4‐isopropyl‐4,5‐dihydrooxazol‐2‐yl)phenol,12 ligands L1 – L4 a 10 and substrates S2 ,13 S3 ,14 S4 ,15 S5 13 and S11 7c were prepared as previously reported. Substrates S6 – S10 were prepared by using the Wittig olefination procedure (for details, see the Supporting Information).…”

Section: Methodsmentioning

confidence: 99%

Unerwartete Kohlenmonoxid‐Gefahren

Bosch¹

2016

Biologie in unserer Zeit

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kommen, Entstehung und Abbau von CO sehr komplex und von vielen Faktoren abhängig. Ozeane gelten als CO-Quellen. Höhere CO-Konzentrationen auf der Nordhalbkugel gehen auf Emissionen und eine längere mittlere Lebensdauer von CO zurück, da die Abbaureaktion zu Kohlendioxid (CO 2 ) in tropischen Breiten schneller abläuft. Pro Jahr werden etwa 2500 Megatonnen CO emittiert oder gebildet, etwa die Hälfte bei Waldbränden und der Nutzung fossiler Brennstoffe [3]. In der Troposphäre unterstützt CO die Ozonbildung. Im Weltraum hat man CO u. a. auf der Sonne, auf Venus und Pluto und in Kometenschweifen nachgewiesen. Blockierte Sauerstoffträger durch COBeim Einatmen gelangt CO über die Lungenbläschen (Alveolen) zu den roten Blutkörperchen (Erythrozyten), die eigentlich mit Sauerstoff beladen die Körper-zellen mit lebenswichtigem Sauerstoff (O 2 ) versorgen sollen. CO verdängt massiv den locker gebundenen Sauerstoff vom roten Blutfarbstoff Hämoglobin (einem Protein in den Erythrozyten), da es eine bis zu 300-fach höhere Affinität zum zweiwertigen Eisen des Hämoglo-bins hat und mit ihm Carboxy-Hämoglobin (CO-Hb) bildet.Zusätzlich wird die Sauerstoffabgabe an das Gewebe erschwert und die Beeinträchtigung wichtiger Cytochrom-Enzyme in der mitochondrialen Atmungskette führt zu einem Sauerstoffmangel ABB . 4 Pelletlager im Haushalt.Bild: intermedichbo.

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Dipole-stabilized carbanions from thioesters. Evidence for stabilization by the carbonyl group

Cited by 24 publications

References 24 publications

1,4-Silatropy of S-α-Silylbenzyl Thioesters: A Convenient Route to Silyl Enol and Dienol Ethers Accompanied by C−C Bond Formation via Thiocarbonyl Ylides

1,4-Silatropy of S-α-Silylbenzyl Thioesters: A Convenient Route to Silyl Enol and Dienol Ethers Accompanied by C−C Bond Formation via Thiocarbonyl Ylides

Dipole-stabilized carbanions: novel and useful intermediates

Unerwartete Kohlenmonoxid‐Gefahren

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