共查询到20条相似文献,搜索用时 15 毫秒
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Huang He Zhang Lei Zhang Xiaodong Ji Xun Ding Xiao Shen Xu Jiang Hualiang Liu Hong 《中国化学》2010,28(6):1041-1043
The total synthesis of Cytosporone B, a naturally occurring agonist for Nur77, has been accomplished. The key steps are the sequential Grignard reaction and Lemieux‐van Rudloff oxidation followed by a deprotection of the methyl aromatic ether to phenol and subsequent Friedel‐Crafts acylation. 相似文献
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Li DR Zhang DH Sun CY Zhang JW Yang L Chen J Liu B Su C Zhou WS Lin GQ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(4):1185-1204
An efficient and highly convergent total synthesis of the potent antitumor agent phorboxazole B has been achieved. The synthetic strategy of this synthesis features: 1) a highly efficient substrate-controlled hydrogenation to construct the functionalized cis-tetrahydropyrane unit; 2) iterative crotyl addition to synthesize the segment that contains alternating hydroxyl and methyl substituents; 3) Hg(OAc)2/I2-induced cyclization to establish the cis-tetrahydropyrane moiety; 4) 1,3-asymmetric induction in the Mukaiyama aldol reaction to afford the stereogenic centers at C9 and C3; and 5) the exploration of the Still-Gennari olefination reaction to complete the macrolide ring of phorboxazoloe B. 相似文献
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The paper illustrates two efficient routes to macrolactone 19 containing a 3-(para-methoxybenzyloxy)propyl side chain at C-15. The chiral center at C-15 was introduced by a Noyori reduction of keto ester 5. The intermediate common to both routes, aldehyde 8, was prepared from keto ester 5. The subsequent chain extension utilized Evans aldol reactions. The first route leads to the alkene 14, which was used, after hydroboration, for a Suzuki cross-coupling reaction with vinyl iodide 15. The derived seco acid 18 was converted into the macrolactone 19 by a Mitsunobu lactonization by using immobilized triphenylphosphine. Alternatively, an aldol reaction of 8 with the 4-pentenoyl derivative 20 was used to prepare alkene 26. This building block led to ester 28, which could also be converted into macrolactone 19 by the classical ring-closing metathesis. After conversion of the C-15 side chain to the corresponding aldehyde, the enamide was introduced through hemiaminal formation and formal elimination of water. Separation of the double-bond isomers and removal of the silyl protecting groups provided salicylihalamides A (E)-1 and B (Z)-1. 相似文献
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Enantioselective Divergent Syntheses of Several Polyhalogenated Plocamium Monoterpenes and Evaluation of Their Selectivity for Solid Tumors 下载免费PDF全文
Carl V. Vogel Halina Pietraszkiewicz Omar M. Sabry Prof. William H. Gerwick Dr. Frederick A. Valeriote Prof. Christopher D. Vanderwal 《Angewandte Chemie (International ed. in English)》2014,53(45):12205-12209
The family of polyhalogenated monoterpenes from Plocamium counts over a hundred known members. Using glyceraldehyde acetonide as a chiral‐pool precursor, an enantioselective and divergent strategy was developed that provides a blueprint for the synthesis of many of the small yet complex acyclic members of this family. The broad applicability of this approach is demonstrated with the short, eight‐step synthesis of four natural products and three analogues. These syntheses are the first of any members of the acyclic polyhalogenated Plocamium monoterpenes and permitted the evaluation of their selectivity against a range of tumor cell lines. 相似文献
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Neutrality is the best policy: Key features of the first total synthesis of paecilospirone include an anti-selective, lactate-derived aldol reaction, and a double deallylation/spirocyclization conducted at neutral pH to construct the sensitive hydroxy-substituted benzannulated spiroacetal (see scheme; Bn=benzyl, TBS=tert-butyldimethylsilyl, TES=triethylsilyl). 相似文献
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Laetirobin, isolated from a parasitic fungus host–plant relationship, was synthesized in six practical steps with an overall yield of 12 % from commercially available 2,4‐dihydroxyacetophenone. Because the product is a pseudosymmetric tetramer of benzo[b]furans, each step of the synthesis was designed to involve tandem operations. Highlights include: 1) the double Sonogashira reaction of a bis(alkyne), 2) the practical copper(I)‐mediated formation of a bis(benzo[b]furan), and 3) the biomimetic [4+2] dimerization and unexpected cationic [5+2] annulation of gem‐diaryl alkene precursors. Preliminary structure–activity relationship data between the isomeric [4+2] and [5+2] tetramers revealed only the natural product to possess promising anticancer potential. Specifically, laetirobin is capable of blocking tumor cell division (mitosis) and invoking programmed cell death (apoptosis). 相似文献
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