Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA.
J Org Chem. 2012 Oct 19;77(20):8933-45. doi: 10.1021/jo301287z. Epub 2012 Oct 1.
We systematically explored a transannular Michael reaction cascade for stereoselective synthesis of polycyclic systems. Both E,Z- and E,E-1,7-bis-enones in the form of 14-membered macrocyclic lactones underwent transannular cyclization to give polycyclic products with high efficiency and excellent diastereoselectivity. In contrast, Z,E- and Z,Z-macrocyclic lactones did not cyclize under similar reaction conditions. Our study revealed similarities and subtle stereochemical differences between this transannular cyclization process and transannular Diels-Alder reactions. An acyl ketene approach was developed for efficient synthesis of macrocyclic lactones. This investigation also illuminated the scope and limitation of macrocyclization by intramolecular Reformatsky reaction to prepare macrocyclic lactones.
我们系统地探索了用于多环系统立体选择性合成的跨环迈克尔反应级联反应。以 14 元大环内酯形式存在的 E,Z-和 E,E-1,7-双烯酮都经历了跨环环化，以高效率和优异的非对映选择性得到多环产物。相比之下，Z,E-和 Z,Z-大环内酯在类似的反应条件下不环化。我们的研究揭示了这种跨环环化过程与跨环 Diels-Alder 反应之间的相似性和细微的立体化学差异。我们开发了一种酰基烯酮方法来高效合成大环内酯。这项研究还阐明了通过分子内 Reformatsky 反应制备大环内酯的环化的范围和限制。
