A Conceptually Different Approach to the Asymmetric Synthesis of α-Substituted Carbonyl Compounds
作者:Keiji Maruoka、Shuichi Nakai、Minoru Sakurai、Hisashi Yamamoto
DOI:10.1055/s-1986-31495
日期:——
A new approach has been demonstrated for the asymmetric synthesis of α-substituted carbonyl compounds. Thus, the key asymmetric carbon-carbon bond formation is accomplished by the highly diastereoselective addition of organoaluminum reagents to the chiral α,β-unsaturated acetal derived from the α,β-unsaturated aldehyde and (R,R)-tartaric acid diamide to furnish the 1,4-adduct preferentially along with the 1,2-adduct as a minor product. Subsequent oxidation of the combined adducts with ozone or the system potassium permanganate/sodium periodate gives rise to the optically active α-substituted aldehyde, ketone, or carboxylic acid, respectively, with high enantioselectivities. The present method has been applied to the facile synthesis of an anti-inflammatory agent and the principal alarm pheromone of the leaf-cutting ant Atta texana in optically active forms.
我们证明了一种不对称合成δ-取代羰基化合物的新方法。因此,关键的不对称碳碳键形成是通过有机铝试剂与来自δ,δ-不饱和醛和(R,R)-酒石酸二酰胺的手性δ,δ-不饱和缩醛的高度非对映选择性加成来完成的,从而优先生成 1,4-加成物以及作为次要产物的 1,2-加成物。 随后用臭氧或高锰酸钾/高碘酸钠体系氧化合并加合物,可分别得到光学活性高的δ-取代醛、酮或羧酸,对映选择性高。本方法已应用于以光学活性形式简便合成一种抗炎剂和切叶蚁 Atta texana 的主要报警信息素。