α‑Lithiobenzyloxy as a Directed Metalation Group in ortho-Lithiation Reactions

The α-lithiobenzyloxy group, easily generated from aryl benzyl ethers by selective α-lithiation with t-BuLi at low temperature, behaves as a directed metalation group (DMG) providing a direct access to o-lithiophenyl α-lithiobenzyl ethers. This ortho-directing effect is reinforced in substrates bear...

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Bibliographic Details
Published in:Organic letters 2020-08, Vol.22 (16), p.6365-6369
Main Authors: Sedano, Carlos, Velasco, Rocío, Feberero, Claudia, Suárez-Pantiga, Samuel, Sanz, Roberto
Format: Article
Language:English
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Summary:The α-lithiobenzyloxy group, easily generated from aryl benzyl ethers by selective α-lithiation with t-BuLi at low temperature, behaves as a directed metalation group (DMG) providing a direct access to o-lithiophenyl α-lithiobenzyl ethers. This ortho-directing effect is reinforced in substrates bearing an additional methoxy group at the meta position. The generated dianions can be reacted with a selection of electrophiles including carboxylic esters and dihalosilanes or germanes, which afford interesting benzofuran, sila­(germa)­dihydrobenzofuran, and silachroman derivatives from simple aryl benzyl ethers.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.0c02199