反应详情

Benzaldehyde (1.6 g, 15 mmol), acetophenone (1.8 g, 15% mmol) and acetic acid (0.3 g, 5 mmol) were combined in a flask under nitrogen. 5-Ethyl-2-methylpyridine borane (0.7 g, 5 mmol) was added via syringe over 5 minutes at room temperature. At the end of the addition the temperature of the reaction mixture reached 70° C. An ice water bath was applied immediately to bring the temperature down. The 1H NMR spectrum indicated that the reaction was complete, giving a 91:9 ratio of benzyl alcohol to phenethylalcohol. Of the combined carbonyl substrates, 37% were reduced and 63% remained unreduced. The 11B NMR spectrum indicated 77% borate (reduced carbonyl products) and 22% (combined species between 0 and 2 ppm) of amine coordinated to borate products.

1. additionAt the end of the addition the temperature of the reaction mixture
2. customreached 70° C
3. customAn ice water bath was applied immediately