Method B). The substrate (0.6 g, 2.33" 01) is reduced at-1.78* 0.08 V in the presence of lb (0.27 mL, 2.4 mmol): n= 2.21; crude product, 0.685 g. The first time, the chromatographic column is eluted with benzene; 13b (23%) and 14d (9%) are thus isolated. Then the column is eluted with diethyl ether, and 0.415 g of a mixture of four compounds is collected. In a second experiment, the column is eluted with 7030 diethyl ether-hexane, and 15d (20%), ...
