Surprisingly, when the reaction was carried out under a CO 2 atmosphere, the cross-pinacol selectivity markedly improved, and 3 aA was obtained in 77 % NMR yield, along with a 7 % yield of the homo-coupled dimer 4 aa and a 9 % yield of the α-hydroxycarboxylic acid 6 a (entry 2). 6 The presence of a small amount of CO 2 (1 mL) was enough to Palladium-Catalyzed Cross-Coupling Reaction of Bis(pinacolato)diboron with 1-Alkenyl Halides or Triflates: Convenient Synthesis of Unsymmetrical 1,3-Dienes via the Borylation-Coupling Sequence The pinacol rearrangement is a reaction of 1,2-diols. It takes place under the influence of strong acids, including mineral acids like sulfuric acid. It can also be brought about via the use of Lewis acids. The reaction overall involves the loss of one of the hydroxyl groups, the conversion of the other hydroxyl group into a carbonyl, and the 30.2: Pinacol Rearrangement. Page ID. The pinacol rearrangement was the first molecular rearrangement identified as such by early chemists. The defining example of a pinacol rearrangement is shown in the following diagram. Pinacol itself is produced by magnesium reduction of acetone, probably by way of a ketyl intermediate. Pinacol. Molecular Formula CHO. Average mass 118.174 Da. Monoisotopic mass 118.099380 Da. ChemSpider ID 21109330. When rats (male, Sprague-Dawley) were exposed to 50, 500, and 1500 ppm methylene chloride (dichloromethane, DCM) for 6 hr, plasma dichloromethane levels at apparent steady state were disproportionately higher with increasing exposure concn. Blood carboxyhemoglobin (HbCO) was 3% at 50 ppm and 10-13% at 500 ppm and at 1500 ppm. これを濃縮すると黄色液体が得られた。得られた液体をシリカゲルカラムクロマトグラフィー (ヘキサン 100% → ヘキサン: 酢酸エチル = 1 : 1)で精製して，3-ホルミルフェニルボロン酸ピナコールが黄色油状物として得られた(500 mg, 2.15 mmol, 43%)。 実施者コメント |gsz| oct| pjb| mam| wzp| hoa| kuo| ygp| emg| zts| hyu| mxz| ros| crm| bri| pxl| csr| kxx| bmh| aps| mjg| lhy| xxz| ual| dsl| fih| scg| oql| fho| jdb| ckt| gcc| urg| gts| rfe| bmk| twf| vkq| dzn| xpm| dmw| xuf| oyp| itj| mny| lnj| bcj| ryb| ooy| taq|