一般而言，該方法主要用于芳基酮或二芳基酮的還原. 如芳環(huán)上帶有許多富電子基團(tuán)或二芳基的酮，這類還原易于進(jìn)行有時不需要加任何 Lewis 酸.
LAH-AlCl3 法示例1
A solution of AlCl 3 (106.7 g, 0.8 mol) in diethyl ether (200 mL) was added slowly to a stirred slurry of LiAlH 4 (15.2 g, 0.4 mol) in ether (100 mL), and the mixture was stirred for 5 min. A solution of 4-methylbenzophenone (49.1 g, 0.25 mol) was then added dropwise, while the reaction mixture was stirred. The exothermic reaction kept the mixture refluxing. When the refluxing stopped, the mixture was stirred for another 15 min, and ethyl acetate (53 mL, 0.55 mol) was added dropwise to decompose excess reagent. The mixture was poured onto ice (300 g) and NH 4 Cl (85 g), and the ethereal layer was separated and washed with saturated sodium chloride solution (100 mL). The aqueous layer was extracted with dichloromethane (2*100 mL), the extracts were combined with the ether solution and driedwith MgSO 4 , and the solvent was evaporated. The crude product was distilled under vacuum (bp 112 o C/0.05 Torr) to yield a pure colorless liquid (42.9 g, 94%). 'H NMR (60 MHz, CDCI,) δ 2.31 (s, 3H, CH,), 3.95 (s, 2 H, CH2), 7.10 (s, 4 H, arom), 7.23 (m, 5 H, arom); MS m/z (re1 intensity) 182 (M + , 74), 181 (18), 167 (IOO), 166 (24), 165(47), 152 (18), 91 (10).
LAH直接還原二芳基酮示例2
A solution of benzophenone (42 g, 0.2 mol) in ether (400 mL) was added dropwise to a solution of lithium aluminum hydride (35.6 g, 0.93 mol) in ether (1400 mL) and the mixture was bolied under reflux for 6 g. The solution was cooled. Then 36 mL of water was added dropwise. The solid was removed and filtrate was concentrated and the risidue distilled (bp 88-90 at 0.027 mmHg) to afford the product (22 g, 61 %), which on collong solidified; mp 30-32 °
