实例 n-CHLi/Et2O H -50至-60CCH3 Co,.1o.c-c COOH CHS C-C H 实 例 C=C C2H5 CH3 I H C=C C2H5 CH3 Li H C=C C2H5 CH3 COOH H n-C4H9Li/Et2O -50 至 -60oC CO2 H2O