Two-Directional Elaboration of Hydroxyacetone under Thermodynamically Controlled Conditions: Allylation or 2-Propynylation and Aldol Reaction
作者:Teruhiko Ishikawa、Toshiaki Aikawa、Eiko Ohata、Takako Iseki、Satoshi Maeda、Takashi Matsuo、Tatsuo Fujino、Seiki Saito
DOI:10.1021/jo0618573
日期:2007.1.1
acceptable yields after acidic treatment of the mixture for dehydration and deprotection. Introducing a chiral auxiliary protecting group into hydroxyacetone led to asymmetric allylation though stereoselectivity was around 50 % ee. Thus, the hidden aspect of the chemoselective nature of protected hydroxyacetone-derived enolate generated under thermodynamically controlled conditions has opened a new avenue for
由O-(四氢吡喃-2-基)羟基丙酮在热力学控制的条件下(1.3当量的NaH,THF,0°C至rt)生成的烯醇化物在带有受保护羟基的碳上具有非常高的区域选择性烯丙基化。当将相当于最初添加的NaH的过量的叔丁基-BuOH引入混合物中,然后添加醛时,在甲基上发生羟醛反应,得到1-取代的4-羟基-(1 E酸处理该混合物以进行脱水和脱保护后,以可接受的收率得到6-庚二烯-3-酮。尽管立体选择性约为50%ee,但将手性辅助保护基引入羟基丙酮会导致不对称烯丙基化。因此,在热力学控制条件下产生的受保护的羟基丙酮衍生的烯醇化物的化学选择性的隐藏方面为羟基丙酮的双向加工开辟了一条新途径,该途径应可潜在地用于有机合成中。