In our strategy for the total synthesis of tylonolide 2, aglycon of tylosin 1, and for the construction of the eastern part C1-C9, we planned to carry out a Hoppe homoaldolisation. In a model study, reaction was performed between racemic titanated crotyl carbamate (±)-3b and optically active aldehydes 6a-c. The expected syn-anti adducts 7a-c were obtained in good isolated yield together with the anti-anti isomer 8a-c. Interestingly, the γ-lactol 6d was also tested and delivered the syn-anti 7d compound in 70% isolated yield.
在泰洛新 1 的苷元泰洛内酯 2 的全合成战略中,为了构建 C1-C9 的东部部分,我们计划进行霍普均醛化反应。在一项模型研究中,外消旋
钛酸巴豆酸酯 (±)-3b 与光学活性醛 6a-c 发生了反应。得到了预期的同反加合物 7a-c 和反反异构体 8a-c,分离收率很高。有趣的是,δ-内酯 6d 也进行了测试,并以 70% 的分离收率得到了合成反式 7d 化合物。