Alkoxy-substituted organolithiums

Recently Yoshida et al. have employed silyl-stabilized a-alkoxy organolithium reagents for the synthesis of a variety of carbonyl compounds. Methoxy(trimethylsilyl)methane and methoxybis(trimethyl-silyl)methane, when deprotonated with Bu Li and Bu"Li respectively, give anions which can be alkylated with a variety of electrophiles. Electrolysis of a solution of the alkylated product in methanol yields, by virtue of the reduced oxidation potential of ethers a-substituted with silicon, either the dimethyl acetal or in the latter case the orthoester. The mildness of the electrolytic process recommends the method for the preparation of a variety of carbonyl compounds. 

Development of the chemistry of the salt (156) continues. When converted into the alkoxyphosphonium salts (157) and treated with, e.g., methyl-lithium or lithium dimethylcuprate, alkylation at the alkoxy carbon to form R—Me derivatives only occurs to a small extent, due to competition from the strongly nucleophilic N-methylanilide ion. However, alkylation (and arylation) at the alkoxy carbon has been achieved by the reaction of the salt (156) with mixed cuprates derived from an allylic alcohol, copper(i) iodide, and an organolithium reagent, enabling direct substitution of the hydroxy-group of allyl alcohols by alkyl or phenyl groups in a regio- and stereo-selective manner. ... 

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