enantioselective catalysts. The salicylaldehyde precursors are synthesized from the silyl ethers of 2,6-dibromophenols via a one-pot double lithium halogen exchanges, to induce an intramolecular retro-Brook rearrangement and allow introduction of the aldehyde group. Condensation of the salicylaldehyde products with a chiral diamine affords the silyl-substituted salen ligands in high yields. The use of other
描述了用于制备对映选择性催化剂的甲
硅烷基取代的塞伦
配体的有效合成。
水杨醛前体是由2,6-二
溴苯酚的甲
硅烷基醚通过一锅双卤化
锂锂交换合成的,以诱导分子内逆布鲁克重排并允许引入醛基。
水杨醛产物与手性二胺的缩合以高收率提供了甲
硅烷基取代的塞伦
配体。使用其他亲电试剂可轻松获得甲
硅烷基取代的
酚酯,酮和
硼酸。