Hamilton Rachael E, Berkley Ellen A, Laufer Iain K, Ruos Madeline E, Smith Brandon, Dahi Anthony N, Gallagher Timothy J, Justo Vanessa, Warner Flannery, Wenzel Anna G
Keck Science Department, Scripps, Claremont McKenna, and Pitzer Colleges, Claremont, California 91711, United States.
J Org Chem. 2024 Dec 20;89(24):18654-18659. doi: 10.1021/acs.joc.4c02062. Epub 2024 Nov 26.
An auxiliary-based protocol is described for an asymmetric allenoate Claisen rearrangement. Silicated tosic acid (10 mol %) was used as an inexpensive, user-friendly catalyst. Stereochemical analysis revealed a preferential attack at the face of prostereogenic olefin. The amine auxiliary was readily hydrolyzed and can be isolated from the reaction mixture (85-87% recovery). The resulting unsaturated β-keto esters were isolated in ≤99% yield and 98% ee. Diastereoselective examples provided a 96:4 : ratio of the resulting vicinal stereocenters.
描述了一种用于不对称烯丙基酯克莱森重排的基于助剂的反应方案。硅胶负载的对甲苯磺酸（10 mol%）被用作一种廉价、使用方便的催化剂。立体化学分析表明，在原手性烯烃的某一面存在优先进攻。胺助剂易于水解，可从反应混合物中分离出来（回收率85 - 87%）。所得不饱和β-酮酯的分离产率≤99%，对映体过量值为98%。非对映选择性的例子给出了所得邻位立体中心96:4的比例。
