The Research Center of Chiral Drugs, Innovation Research Institute of Traditional Chinese Medicine and China-Thailand Joint Research Institute of Natural Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, 201203, Shanghai, China.
CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, 200032, Shanghai, China.
Nat Commun. 2020 Oct 30;11(1):5480. doi: 10.1038/s41467-020-19293-9.
Catalytic asymmetric conjugate allylation of unsaturated carbonyl compounds is usually difficult to achieve, as 1,2-addition proceeds dominantly and high asymmetric induction is a challenging task. Herein, we disclose a copper(I)-NHC complex catalyzed asymmetric 1,6-conjugate allylation of 2,2-dimethyl-6-alkenyl-4H-1,3-dioxin-4-ones. The phenolic hydroxyl group in NHC ligands is found to be pivotal to obtain the desired products. Both aryl group and alkyl group at δ-position are well tolerated with the corresponding products generated in moderate to high yields and high enantioselectivity. Moreover, both 2-substituted and 3-substituted allylboronates serve as acceptable allylation reagents. At last, the synthetic utility of the products is demonstrated in several transformations by means of the versatile terminal olefin and dioxinone groups.
铜（I）-NHC 配合物催化的不饱和羰基化合物的不对称共轭烯丙基化通常难以实现，因为 1,2-加成占主导地位，而高对映选择性是一项具有挑战性的任务。在此，我们披露了一种铜（I）-NHC 配合物催化的 2,2-二甲基-6-烯基-4H-1,3-二氧杂环戊烯-4-酮的不对称 1,6-共轭烯丙基化。发现 NHC 配体中的酚羟基对于获得所需产物至关重要。δ-位的芳基和烷基均能很好地耐受，相应的产物以中等至较高的收率和高对映选择性生成。此外，2-取代和 3-取代的烯丙基硼酸酯都可用作可接受的烯丙基化试剂。最后，通过末端烯烃和二氧杂环戊酮的多功能性，证明了产物在几种转化中的合成实用性。
