respectively), and thus C-alkylated on sarcosine (Sar) moieties with MeI and allyl or PhCH2Br. The polylithiatedspecies are solubilized in THF, and their reactivity modified by excess base (lithium diisopropylamide (LDA)), by added LiCl, and/or the cosolvent N,N′-dimethylpropyleneurea (DMPU). Optimization of the reaction conditions for methylation in the cases of 7b (Table 3) and 12b (Scheme 8) gave products