Sedano Carlos, Velasco Rocío, Feberero Claudia, Suárez-Pantiga Samuel, Sanz Roberto
Área de Química Orgánica, Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Pza. Misael Bañuelos s/n, 09001-Burgos, Spain.
Org Lett. 2020 Aug 21;22(16):6365-6369. doi: 10.1021/acs.orglett.0c02199. Epub 2020 Aug 3.
The α-lithiobenzyloxy group, easily generated from aryl benzyl ethers by selective α-lithiation with -BuLi at low temperature, behaves as a directed metalation group (DMG) providing a direct access to -lithiophenyl α-lithiobenzyl ethers. This -directing effect is reinforced in substrates bearing an additional methoxy group at the 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.
α-锂代苄氧基可通过在低温下用叔丁基锂对芳基苄基醚进行选择性α-锂化轻松生成，它作为一个定向金属化基团（DMG），可直接用于制备α-锂代苯基α-锂代苄基醚。在邻位带有额外甲氧基的底物中，这种定向作用会增强。生成的双负离子可与多种亲电试剂反应，包括羧酸酯、二卤硅烷或二卤锗烷，这些反应能从简单的芳基苄基醚制得有趣的苯并呋喃、硅（锗）二氢苯并呋喃和硅杂色满衍生物。
