[CH3:1][Si:2]([NH-:5])([CH3:4])[CH3:3].[CH3:6][Si:7]([NH-])([CH3:9])[CH3:8].[Li+:11].[Li+].COC1[C@@H](O)[C@@H]2[C@@]3(N(CCC4C2=CC2OCOC=2C=4)CCC3)C=1.C(OC(=O)C)(=O)C>O1CCCC1.C([Li])CCC>[CH3:1][Si:2]([N-:5][Si:7]([CH3:9])([CH3:8])[CH3:6])([CH3:4])[CH3:3].[Li+:11]A commercial solution of lithium bis-(trimethylsilylamide) 1M in tetrahydrofurane (0.95 ml, 0.95 mmol) was added to a stirred solution of (−)-cephalotaxine (200 mg, 0.63 mmol) in anhydrous tetrahydrofurane at −40° C. After stirring for 5 minutes, acetic anhydride (90 μl, 0.95 mmol) was added, and the reaction mixture was treated like method above-mentioned in 1°). The product thus obtained showed identical characteristics to this obtained above in butyllithium method.
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