Loke Inga, Bentzinger Guillaume, Holz Julia, Raja Aruna, Bhasin Aman, Sasse Florenz, Köhn Andreas, Schobert Rainer, Laschat Sabine
Institut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
Org Biomol Chem. 2016 Jan 21;14(3):884-94. doi: 10.1039/c5ob01491c. Epub 2015 Nov 24.
In order to construct the functionalized AB ring system of clifednamide, member of the class of macrocyclic tetramic acid lactams, a synthesis was developed which utilized an Ireland-Claisen rearrangement and an intramolecular Diels-Alder reaction. Starting from di-O-isopropylidene-d-mannitol the allyl carboxylate precursor for the sigmatropic rearrangement was prepared. This rearrangement proceeded diastereoselectively only in the presence of an allyl silyl ether instead of the parent enone in the side chain, as suggested by deuteration experiments. A subsequent Diels-Alder reaction yielded the target ethyl hexahydro-1H-indene-carboxylate with high diastereoselectivity. Quantum-chemical investigations of this intramolecular Diels-Alder reaction support the proposed configuration of the final product.
为了构建大环四酰胺内酯类成员克利夫地奈德的官能化AB环体系，开发了一种利用爱尔兰-克莱森重排和分子内狄尔斯-阿尔德反应的合成方法。从二-O-异亚丙基-d-甘露醇开始，制备了用于[3,3] - 迁移重排的烯丙基羧酸酯前体。如氘代实验所示，这种重排仅在侧链存在烯丙基硅醚而非母体烯酮的情况下以非对映选择性方式进行。随后的狄尔斯-阿尔德反应以高非对映选择性得到目标产物六氢-1H-茚-羧酸乙酯。对该分子内狄尔斯-阿尔德反应的量子化学研究支持了最终产物的提议构型。
