167170-55-0Relevant articles and documents
Lithiation reactions catalyzed by linear and cross-linked arene-based polymers. Generation of functionalized organolithium compounds
Candela,Gomez,Yus
, p. 795 - 801 (2007/10/03)
Lithiation of various substrates, such as chlorinated acetals, α-chloro ether, dichloro derivatives benzo-fused heterocycles, and allyl and benzyl derivatives, with excess lithium powder in the presence of a catalytic amount of soluble linear or insoluble cross-linked arene (naphthalene or biphenyl)-based polymers yields the expected organolithium intermediates. The latter react with electrophiles either in two steps or under Barbier-type reaction conditions to afford the corresponding adducts. The catalyst is easily recuperated by filtration at the end of the process, and the procedure can be regarded as a reasonable alternative to the use of free arenes as electron carrier in lithiation reactions.
Lithium 2-(2-lithiomethylphenyl)ethanolate from isochroman: Easy preparation of substituted benzoxepines and functionalised arenes
Almena, Juan,Foubelo, Francisco,Yus, Miguel
, p. 3365 - 3374 (2007/10/02)
The reaction of isochroman (1) with an excess of lithium powder and a catalytic amount of DTBB (2.5 mol %) in THF at 20°C yields the title intermediate, which by reaction with different electrophiles (H2O, D2O, CO2 and carbonyl compounds) at temperatures ranging between -78 and 20°C yields, after hydrolysis, the corresponding products 3. Diols 3h-m, derived from benzaldehyde or ketones, give upon treatment with 85% phosphoric acid the corresponding benzoxepines 5h-m. In the other cases, Friedel-Crafts products resulting from a rearrangement of the first carbenium ion formed, are obtained.
