Amidines nucleophilic epoxidation

Eliminations of epoxides lead to allyl alcohols. For this reaction to take place, the strongly basic bulky lithium dialkylamides LDA (lithium diisopropylamide), LTMP (lithium tetramethylpiperidide) or LiHMDS (lithium hexamethyldisilazide) shown in Figure 4.18 are used. As for the amidine bases shown in Figure 4.17, the hulkiness of these amides guarantees that they are nonnucleophilic. They react, for example, with epoxides in chemoselective E2 reactions even when the epoxide contains a primary C atom that easily reacts with nucleophiles (see, e.g., Figure 4.18). 

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