Wu Haibo, Zheng Zhiyao, Zhang Kaiheng, Kajanus Johan, Johansson Magnus J, Córdova Armando, Bäckvall Jan-E
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691, Stockholm, Sweden.
Department of Natural Sciences, Mid Sweden University, Holmgatan 10, 85179, Sundsvall, Sweden.
Angew Chem Int Ed Engl. 2023 Dec 11;62(50):e202314512. doi: 10.1002/anie.202314512. Epub 2023 Nov 10.
Classical Crabbé type S 2' substitutions of propargylic substrates has served as one of the standard methods for the synthesis of allenes. However, the stereospecific version of this transformation often requires either stoichiometric amounts of organocopper reagents or special functional groups on the substrates, and the chirality transfer efficiency is also capricious. Herein, we report a sustainable methodology for the synthesis of diverse 1,3-di and tri-substituted allenes by using a simple and cheap cellulose supported heterogeneous nanocopper catalyst (MCC-Amp-Cu(I/II)). This approach represents the first example of heterogeneous catalysis for the synthesis of chiral allenes. High yields and excellent enantiospecificity (up to 97 % yield, 99 % ee) were achieved for a wide range of di- and tri-substituted allenes bearing various functional groups. It is worth noting that the applied heterogeneous catalyst could be recycled at least 5 times without any reduced reactivity. To demonstrate the synthetic utility of the developed protocol, we have applied it to the total synthesis of several chiral allenic natural products.
经典的炔丙基底物的克拉贝S型2'取代反应一直是合成丙二烯的标准方法之一。然而，这种转化的立体专一性版本通常需要化学计量的有机铜试剂或底物上的特殊官能团，而且手性转移效率也不稳定。在此，我们报道了一种可持续的方法，通过使用简单且廉价的纤维素负载的非均相纳米铜催化剂（MCC-Amp-Cu(I/II)）来合成多种1,3-二取代和三取代丙二烯。这种方法代表了非均相催化合成手性丙二烯的首个实例。对于一系列带有各种官能团的二取代和三取代丙二烯，均实现了高产率和优异的对映体选择性（产率高达97%，对映体过量值高达99%）。值得注意的是，所应用的非均相催化剂可以循环使用至少5次，而反应活性没有任何降低。为了证明所开发方法的合成实用性，我们已将其应用于几种手性丙二烯类天然产物的全合成。
