2-[N-(Diphenylmethyleneamino)]alkyl carbamates are deprotonated by means of sec-butyllithium in the presence of TMEDA or (-)-sparteine and the diastereomeric ion pairs of α-oxycarbanions formed are substituted by several electrophiles. Deprotection proceeds smoothly to yield chain-elongated β-amino alcohols. Problems arise due to nucleophilic attack of the alkyllithium at one aryl ring of the benzophenone imines under certain reaction conditions.
2-[N-(二苯甲烯
氨基)]烷基
氨基甲酸酯在TME
DA或(-)-斯巴特因存在下被sec-丁基
锂去质子化,形成的二叠体离子对的α-氧基碳负离子被多种电亲体取代。去保护反应顺利进行,生成链延长的β-
氨基醇。在某些反应条件下,烷基
锂对苯基酮
亚胺的一个芳环发生亲核攻击,导致问题出现。