5-O-tert-butyldimethylsilyl-7-O-trimethylsilyl-4''-deoxy-4''-exo-(carboxyethylmethylene)avermectin B1b 、 5-O-tert-butyldimethylsilyl-7-O-trimethylsilyl-4''-deoxy-4''-exo-(carboxyethylmethylene)avermectin B1a 在
sodium tetrahydroborate 、 nickel dichloride 作用下,
以
甲醇 、
乙酸乙酯 为溶剂,
生成
5-O-tert-butyldimethylsilyl-7-O-trimethylsilyl-4''-deoxy-4''-(R)-(acetic acid ethyl ester)avermectin B1b 、 5-O-tert-butyldimethylsilyl-7-O-trimethylsilyl-4''-deoxy-4''-(R)-(acetic acid ethyl ester)avermectin B1a