Catalytic Asymmetric Epoxidation of α,β-Unsaturated Amides: Efficient Synthesis of β-Aryl α-Hydroxy Amides Using a One-Pot Tandem Catalytic Asymmetric Epoxidation−Pd-Catalyzed Epoxide Opening Process
作者:Tetsuhiro Nemoto、Hiroyuki Kakei、Vijay Gnanadesikan、Shin-ya Tosaki、Takashi Ohshima、Masakatsu Shibasaki
DOI:10.1021/ja028454e
日期:2002.12.1
catalytic asymmetric epoxidation of alpha,beta-unsaturated amides using Sm-BINOL-Ph3As=O complex was succeeded. Using 5-10 mol % of the asymmetric catalyst, a variety of amides were epoxidized efficiently, yielding the corresponding alpha,beta-epoxy amides in up to 99% yield and in more than 99% ee. Moreover, the novel one-pot tandem process, one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide
使用Sm-BINOL-Ph3As=O配合物催化α,β-不饱和酰胺的不对称环氧化反应取得成功。使用 5-10 mol% 的不对称催化剂,可以有效地环氧化各种酰胺,以高达 99% 的产率和超过 99% 的 ee 生成相应的 α,β-环氧酰胺。此外,还开发了一种新型的一锅串联工艺,即一锅串联催化不对称环氧化-钯催化的环氧化物开环工艺。该方法已成功用于β-芳基α-羟基酰胺的有效合成,包括β-芳基乳糖基-亮氨酸甲酯。有趣的是,发现 Pd 催化剂的有益改性是通过第一次环氧化的成分实现的,就化学选择性而言,产生了更适合 Pd 催化的环氧化物开环反应的催化剂。