104(P-56) 過酸化水素を用いる効率的合成法の研究 : 触媒的不斉スルホ酸化およびBaeyer-Villiger反応の開発(ポスター発表の部)

概要

論文の詳細を見る
Hydrogen peroxide is a highly atom-efficient oxidant and its use as terminal oxidant for catalytic oxidation is strongly recommended, especially for realizing practical asymmetric oxidation reactions. However, there are only a few catalysts available for this purpose. In this paper, we describe our new findings that metallosalen complexes which can adopt cis-β structure upon substrate or oxidant coordination are suitable catalysts for asymmetric oxidation reactions such as sulfoxidation and Bayer-Villiger oxidation, useful reactions for organic synthesis. 1. Asymmetric Sulfoxidation Treatment of sulfides with urea hydrogen peroxide addition compound (UHP) in the presence of a catalytic amount of chiral di-μ-oxo-Ti(salen) complex 4 was found to provide the corresponding sulfoxides with high enantioselectivity (>90%ee). A wide range of sulfides, alkyl aryl sulfides, dialkyl sulfides, 2-substituted 1,3-dithianes, and 2-substituted 1,3-oxathiane, can be used as the substrates for this reaction. 2. Asymmetric Baeyer-Villiger Oxidation Baeyer-Villiger oxidation of racemic and prochiral cyclobutanones using UHP as the oxidant was found to proceed with high enantiosepecificity or enantiotopos selectivity (>80%ee) to give the corresponding γ-butyrolactones, when Zr(salen) 7 was used as the catalyst. It is noteworthy that enantiotopos selection by 7 overrides usual migratory attitude observed in Baeyer-Villiger reaction: the reaction of the slow isomer of racemic ketones gives abnormal lactone preferentially. In conclusion, we were able to demonstrate that metallosalen complexes possessing or dynamically taking cis-β structure served as efficient catalysts for asymmetric sulfoxidation and Baeyer-Villiger oxidation.
天然有機化合物討論会の論文
2002-09-01

104(P-56) 過酸化水素を用いる効率的合成法の研究 : 触媒的不斉スルホ酸化およびBaeyer-Villiger反応の開発(ポスター発表の部)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク