16765-34-7Relevant academic research and scientific papers
α-Lithiated Aryl Benzyl Ethers: Inhibition of [1,2]-Wittig Rearrangement and Application to the Synthesis of Benzo[b]furan Derivatives
Velasco, Rocío,Feberero, Claudia,Sanz, Roberto
, p. 4416 - 4419 (2015)
The use of t-BuLi at low temperature selectively leads to α-lithiation of benzyl phenyl ether generating a stable organolithium, which can be efficiently trapped with a variety of selected electrophiles prior to suffering the expected [1,2]-Wittig rearrangement. In the case of (o-alkynyl)phenyl benzyl ethers, the intermediate α-aryloxyorganolithium undergoes an unexpected anti intramolecular carbolithiation reaction leading to functionalized benzo[b]furan derivatives.
Exploring the Reactivity of α-Lithiated Aryl Benzyl Ethers: Inhibition of the [1,2]-Wittig Rearrangement and the Mechanistic Proposal Revisited
Velasco, Rocío,Silva López, Carlos,Nieto Faza, Olalla,Sanz, Roberto
supporting information, p. 15058 - 15068 (2016/10/11)
By carefully controlling the reaction temperature, treatment of aryl benzyl ethers with tBuLi selectively leads to α-lithiation, generating stable organolithiums that can be directly trapped with a variety of selected electrophiles, before they can undergo the expected [1,2]-Wittig rearrangement. This rearrangement has been deeply studied, both experimentally and computationally, with aryl α-lithiated benzyl ethers bearing different substituents at the aryl ring. The obtained results support the competence of a concerted anionic intramolecular addition/elimination sequence and a radical dissociation/recombination sequence for explaining the tendency of migration for aryl groups. The more favored rearrangements are found for substrates with electron-poor aryl groups that favor the anionic pathway.
