Based on Deprotonation of Selenides that have an Additional Anion-stabilizing Group

The phosphorus reagent (42) can be alkylated with alkyl halides. The products (43) can be deprotonated (by NaH or BuLi) and then used in Wittig reactions to afford vinyl selenides as E/Z mixtures.  

Deprotonation (by LDA) of (47) followed by reaction with benzaldehyde, formaldehyde, or propanal gives (48 R = Ph, H, or Et).  

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Applications Based on Deprotonation of Selenides that have an Additional Anion-stabilizing Group. The salt (37) was treated with a variety of aldehydes and, where the resulting yS-hydroxy-selenides were separable, they easily afforded cf/ -unsaturated esters by an elimination process. - The various methods for the elimination are usually stereospecific (Scheme 10). The salts (38), (39), (40), and (41) (all generated by deprotonation) behave similarly, and the methyl analogue of the last compound has been used for the construction of cc-methylene lactones (Scheme 11). Salts (37), (39), and (40) give mainly 1,2-adducts with... 

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