Diisobutylaluminum hydride → 1,4,7-Trioxaspiro[4.4]nonan-8-ol
Reaktionsgleichung
[O:1]1[C:5]2([CH2:9][C:8](=[O:10])[O:7][CH2:6]2)[O:4][CH2:3][CH2:2]1.CC(C[AlH]CC(C)C)C>ClCCl>[O:1]1[C:5]2([CH2:9][CH:8]([OH:10])[O:7][CH2:6]2)[O:4][CH2:3][CH2:2]1Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
A solution of 1,4,7-trioxaspiro[4.4]nonan-8-one (prepared from tetronic acid and ethylene glycol) (3.81 g, 26.5 mmol) in dichloromethane (20 mL) at -78° C. was treated with 32 mL of 1.0 M DIBAL in dichloromethane (32.0 mmol). The mixture was stirred one hour, quenched at -78° C. with water (12 mL total) and stirred at 25° C. until complete decomposition of the aluminum complex (two hours). The granular precipitate of alumina was filtered off, and the product was purified by flash chromatography (ether) to give Compound 7 (3.32 g, 84 percent) as a low melting solid; Rf =0.16 (Et2O); IR (thin film) νmax 3446 (bs), 1720 (w) cm-1 ; 1H NMR (500 MHz, CDCl3) δ 5.51 (bd, J =4.7 Hz, 1 H, OCHOH), 3.96-3.73 (m, 7 H, CH2 --O, OCH2CH2O, OH), 2.27 (dd, J =5.4, 13.7 Hz, 1 H, CHH), 2.05 (dd, J = 1.8, 13.7 Hz, 1 H, CHH); 13C NMR (125 MHz, CDCl3) δ 114.8, 98.2, 72.5, 64.8, 64.7, 43.1; FAB HRMS (NBA/NaI) m/e 169.0477, M+NA+ calcd for C6H10O4 169.0477.