A simple and efficient Knoevenagel condensation between a b-unsaturated aldehydes and active methylene compounds is reported.Notably,this condensation can be catalyzed by PPL（lipase from porcine pancreas） with satisfied yields（49%–92%）.Moreover,PPL induces moderate Z/E selectivity in the Knoevenagel condensation.
Zhi WangChun-Yu WangHao-Ran WangHong ZhangYa-Lun SuTeng-Fei JiLei Wang
Enantioselective transesterification of glycidol with vinyl butyrate as an acyl donor was investigated in the presence of Bacillus subtilis lipase（BSL2） as catalyst. Comparison studies demonstrate the advantage of ultrasound over the conventional shaking for the enzymatic reaction in non-aqueous media. The effects of reaction conditions（ultrasound power, temperature, water activity and pH） on the activity and enantioselectivity were also investigated. Under the optimum conditions, the synthetic activity of BSL2 was 2.95 μmol？min？1？mg？1 and the enantioselectivity（E value） was 52.2. Compared with conventional shaking, ultrasound made the synthetic activity and the enantioselectivity increase 9.5-fold and 1.4-fold, respectively. Furthermore, the repeated use of BSL2 for five cycles resulted in no obvious loss of enzyme activity, suggesting that the enzyme is stable under low power ultrasound conditions.
AN Bai-yiXIE Xiao-naXUN Er-naWANG Jia-xinWANG RenSUN Ruo-xiWANG LeiWANG Zhi
