Enantioselective Synthesis of Tertiary α,α-Diaryl Carbonyl Compounds Using Chiral <i>N,N′</i>-Dioxides under Umpolung Conditions
作者:Tae-Woong Um、Girim Lee、Seunghoon Shin
DOI:10.1021/acs.orglett.0c00333
日期:2020.3.6
addition of the chiral N,N'-dioxide into ynamides generated enolonium ions in situ which underwent enantioselective alkylation by indoles, pyrroles, and phenols, without racemization of the formed tertiary center. This external oxidant approach allows for the use of unmodified nucleophiles and does not leave trace groups from the oxidant, which significantly increases the synthetic efficiency and the
布朗斯台德酸催化的手性N,N'-二氧化物加成到酰胺中,生成原位的en离子,该离子通过吲哚,吡咯和苯酚进行对映选择性烷基化,而没有消旋形成的叔中心。这种外部氧化剂方法允许使用未修饰的亲核试剂,并且不会从氧化剂中留下痕量基团,从而显着提高了合成效率和产物多样性。此外,N,N'-二氧化物的副产物可以有效地再循环成光学纯的形式。