Lewis Acid Catalyzed Enantioselective Photochemical Rearrangements on the Singlet Potential Energy Surface
作者:Malte Leverenz、Christian Merten、Andreas Dreuw、Thorsten Bach
DOI:10.1021/jacs.9b12068
日期:2019.12.26
The oxadi-π-methane rearrangement of 2,4-cyclohexadienones to bicyclic ketones was found to proceed with high enantioselectivity (92–97% ee) in the presence of catalytic amounts of a chiral Lewis acid (15 examples, 52–80% yield). A notable feature of the transformation is the fact that it proceeds on the singlet hypersurface and that no triplet intermediates are involved. Rapid racemic background reactions
发现在催化量的手性路易斯酸(15 个例子,52-80% 产率)存在下,2,4-环己二烯酮的 oxadi-π-甲烷重排以高对映选择性(92-97% ee)进行)。转换的一个显着特征是它在单线态超曲面上进行并且不涉及三线态中间体。因此避免了快速的外消旋背景反应,并且催化剂负载可以保持低(10 mol%)。计算研究表明,通过锥形交叉点在路易斯酸结合的单线态中间体中确定对映选择性。该方法的实用性通过天然产物反菊酸的简洁合成得到了证明。