53101-93-2

3-Lithiofuran is used as a nucleophilic organolithium reagent useful for alkylation; addition to ketones, acid chlorides, aldehydes, amides, lactones, carbon dioxide, nitrones, epoxides, sulfinate esters, boronic esters, metal carbonyls, borates, metal halides; affords intermediates for organometallic coupling reactions.

3-Lithiofuran (1) (eq 1) is prepared by the treatment of 3-iodofuran (2a) with n-Butyllithium in ether or THF (-78 °C); by the treatment of 3-bromofuran (2b) with n-butyllithium in THF (-78 °C); or by the reaction of 3-tri-n-butylstannylfuran (2c) with n-butyllithium in THF (-78 °C).

3-Lithiofuran is generated in situ, under anhydrous conditions in an inert atmosphere at low temperatures (<=-40 °C), and used shortly after preparation. It has been demonstrated that good temperature control is important to the regiochemical integrity of the reagent. Temperatures exceeding -40 °C during the course of reagent generation and use permit isomerization of 3-lithiofuran to the more thermodynamically stable 2- lithiofuran.