Asymmetric Retro-Claisen Reaction by Synergistic Chiral Primary Amine/Palladium Catalysis
作者:Yanfang Han、Long Zhang、Sanzhong Luo
DOI:10.1021/acs.orglett.9b02491
日期:2019.9.20
We described herein a chiral primaryamine/palladium catalyzed asymmetric retro-Claisen reaction of β-diketones with salicylic carbonates. A series of chiral α-alkylated ketones and macrolides were obtained with good yields and excellent enantioselectivities upon a sequence of decarboxylative benzylation, retro-Claisen cleavage, and enamine protonation. This strategy features broad substrate scope
Neighboring group participation in Lewis acid-promoted [3 + 4] and [3 + 5] annulations. The synthesis of oxabicyclo[3.n.1]alkan-3-ones
作者:Gary A. Molander、Kimberly O. Cameron
DOI:10.1021/ja00056a002
日期:1993.2
2-(alkoxycarbon)-m-oxabicyclo[3.n.1]alkan-3-ones can be constructed by this process in which two new carbon-carbon bonds are generated. Unusually high regioncontrol is observed, and good to excellent stereochemicalcontrol can be achieved at virtually every position on the new carbocycles. Intramolecular neighboringgroupparticipation is proposed to explain the unusually high selectivities attained in the annulation
Asymmetric Retro-Claisen Reaction by Chiral Primary Amine Catalysis
作者:Yunbo Zhu、Long Zhang、Sanzhong Luo
DOI:10.1021/jacs.6b00627
日期:2016.3.30
The communication describes an enamine-based asymmetric retro-Claisen reaction of β-diketones by primaryamine catalysis. The reaction proceeds via a sequence of stereoselective C-C formation, C-C cleavage, and a highly stereospecific enamine protonation to afford chiral α-alkylated ketones or macrolides with high yields and enantioselectivities. A detailed mechanism was explored on the basis of experimental
该通讯描述了伯胺催化下 β-二酮的基于烯胺的不对称逆克莱森反应。该反应通过一系列立体选择性 CC 形成、CC 裂解和高度立体有择的烯胺质子化进行,以提供具有高产率和对映选择性的手性 α-烷基化酮或大环内酯。在实验证据和计算研究的基础上探索了详细的机制,以解释观察到的立体控制。
Acylketene acetals in organic synthesis.
作者:Clark N. Eid、Joseph P. Konopelski
DOI:10.1016/s0040-4020(01)80937-6
日期:1991.1
reactivity of achiral and enantiomerically pure acylketene acetals are described. The key reactions of these substrates involve facile conjugate hydroboration and organolithium addition. Enantiomerically pure acylketene acetals were employed to generate a homochiral β-keto ketal through a highly diastereoselective lithium enolate quench. This β-keto ketal, which was also prepared through a desymmetrization