共查询到20条相似文献，搜索用时 15 毫秒
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Guang Li Xiaoni Xie Liansuo Zu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(35):10639-10642
Reported herein is the total synthesis of calophyline A, an indoline natural product possessing distinct ring connectivity which has not been synthesized previously. The synthetic route features several key transformations, including an aza‐pinacol rearrangement to construct the nitrogen‐containing bridged [3.2.2] bicycle, a Heck cyclization to assemble the fused 6/5/6/5 ring system, and a challenging late‐stage aldol reaction to generate both a neopentyl quaternary stereogenic center and an oxygen‐containing bridged [3.2.1] bicycle. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7592-7595
The first total synthesis of the hexacyclic indole alkaloid (±)‐corymine is described. Starting from the readily available N‐protected tryptamine, the title compound was achieved in 21 steps in 3.4 % overall yield. Key steps of the synthesis include: a) the addition of a malonate to a 3‐bromooxindole to afford 3,3‐disubstituted oxindole, b) the formation of a 12‐membered cyclic enol ether by intramolecular O‐propargylation, immediately followed by propargyl Claisen rearrangement to provide the α‐allenyl ketone stereospecifically, c) DMDO oxidation to install a hydroxy group in a highly stereoselective manner, and d) the SmI2‐mediated reductive C−O bond cleavage to remove the α‐keto carboxyl group. 相似文献
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Guang Li Cyril Piemontesi Qian Wang Jieping Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(9):2896-2900
Controlling the cis C20/C21 relative stereochemistry remains an unsolved issue in the synthesis of eburnane‐type indole alkaloids. Provided herein is a simple solution to this problem by developing a unified and diastereoselective synthesis of four representative members of this class of natural products, namely, eburnamonine, larutensine, terengganensine B, and melokhanine E. The synthesis features the following key steps: a) an α‐iminol rearrangement transforming the 3‐hydroxyindolenine into spiroindolin‐3‐one, b) a highly diastereoselective conformation‐directed cyclization leading to the melokhanine skeleton with the desired C20/C21 cis stereochemistry, and c) either an aza‐pinacol or an unprecedented α‐aminoketone rearrangement converting spiroindolinone back into the indole skeleton. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(33):10094-10098
The asymmetric synthesis of (−)‐N ‐methylwelwitindolinone B isothiocyanate is reported. Critical challenges overcome through these studies include the stereoselective installation of the sterically congested C13 alkyl chloride and control of the wayward reactivity of the indole unit to standard oxidants. A Pt‐catalyzed hydrosilylation helped stymie unwanted rearrangements facilitated by vinyl group participation during the chloride installation step, and a new FeII‐catalyzed oxidation accomplished the problematic conversion of indole into 2‐indolinone. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(40):12445-12449
Herein we report a total synthesis of the indolohydroazocine natural product actinophyllic acid. The target molecule was retrosynthetically deconvoluted to render a greatly simplified and symmetrical [4.4.1] bicyclic trienone, the desymmetrization of which was carefully examined under a variety of conditions, including oxidative, reductive, and transition‐metal‐catalyzed transformations. Ultimately, the successful synthetic strategy featured chemoselective catalytic dihydroxylation, desymmetrizing nitrile oxide dipolar cycloaddition, and palladium‐catalyzed aminoarylation to sequentially modify the three olefins within the trienone, followed by a late‐stage reductive cascade indolization and alkylation to complete the target molecule. 相似文献
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