28043-10-9Relevant articles and documents
TiF4-mediated biomimetic alkylation-cyclization cascade reaction of 2-trimethylsilylmethyl-1,5-dienes with aldehydes
Anastasia, Luigi,Giannini, Elios,Zanoni, Giuseppe,Vidari, Giovanni
, p. 5803 - 5806 (2005)
TiF4 has proven to be the Lewis acid of choice for promoting the biomimetic addition of 2-trimethylsilylmethyl-1,5-dienes to aliphatic aldehydes with concomitant cyclization. 1,3-cis-Disubstituted methylenecyclohexanes are thus produced in good yields and high diastereoselectivity. The reaction appears to proceed via a highly concerted mechanism involving a chair-like transition state.
Electrophilic cyclization of polyene allylsylanes. Synthesis of albicanyl acetate
Armstrong, Rosemary J.,Harris, Francis L.,Weiler, Larry
, p. 673 - 675 (1982)
The allylsilanes 5 (a, R=(CH3)2CCHCH2; b, R=(CH3)2CCHCH2CH2C(CH3)CHCH2) were prepared by a nickel(II) catalyzed coupling of trimethylsilylmethylmagnesium chloride with the enol phosphate of the corresponding β-keto esters.Stannic chloride and mercuric trifluoroacetate effected a cyclization of 5.The product from 5b was converted into the marine natural product, albicanyl acetate (1).
Total synthesis of viridicatumtoxin B and analogues thereof: Strategy evolution, structural revision, and biological evaluation
Nicolaou,Hale, Christopher R. H.,Nilewski, Christian,Ioannidou, Heraklidia A.,Elmarrouni, Abdelatif,Nilewski, Lizanne G.,Beabout, Kathryn,Wang, Tim T.,Shamoo, Yousif
supporting information, p. 12137 - 12160 (2014/11/08)
The details of the total synthesis of viridicatumtoxin B (1) are described. Initial synthetic strategies toward this intriguing tetracycline antibiotic resulted in the development of key alkylation and Lewis acid-mediated spirocyclization reactions to form the hindered EF spirojunction, as well as Michael-Dieckmann reactions to set the A and C rings. The use of an aromatic A-ring substrate, however, was found to be unsuitable for the introduction of the requisite hydroxyl groups at carbons 4a and 12a. Applying these previous tactics, we developed stepwise approaches to oxidize carbons 12a and 4a based on enol- and enolate-based oxidations, respectively, the latter of which was accomplished after systematic investigations that revealed critical reactivity patterns. The herein described synthetic strategy resulted in the total synthesis of viridicatumtoxin B (1), which, in turn, formed the basis for the revision of its originally assigned structure. The developed chemistry facilitated the synthesis of a series of viridicatumtoxin analogues, which were evaluated against Gram-positive and Gram-negative bacterial strains, including drug-resistant pathogens, revealing the first structure-activity relationships within this structural type.
Total synthesis and structural revision of viridicatumtoxin B
Nicolaou,Nilewski, Christian,Hale, Christopher R. H.,Ioannidou, Heraklidia A.,Elmarrouni, Abdelatif,Koch, Lizanne G.
, p. 8736 - 8741 (2013/09/12)
Will the real viridicatumtoxin B please stand up: The total synthesis of viridicatumtoxin B resulted in its structural revision and opens the way for analogue construction and biological evaluation of this complex tetracycline-like antibiotic. The highly convergent strategy employed allows for swift construction of the entire carbocyclic framework of the molecule. Copyright
Isolation, synthesis, and anti-tumor activities of a novel class of podocarpic diterpenes
Xiong, Yi,Wang, Kuiwu,Pan, Yuanjiang,Sun, Hongxiang,Tu, Jue
, p. 786 - 789 (2007/10/03)
A novel unusual 17-carbon diterpenoid, named (+)-7-deoxynimbidiol, was isolated from the stalks of Celastrus hypoleucus (Oliv.) Warb. Its racemate and derivatives were synthesized, and the inhibitory activities of these compounds against four cultured human-tumor cell lines were evaluated. The structure-activity relationship was discussed.
CYCLIZATION OF ACYCLIC ISOPRENOIDS. III. MOLECULAR REARRANGEMENTS OF PSEUDODAMASCONES AND GERANATE ESTERS
Gavrilyuk, O. A.,Korchagina, D. V.,Bagryanskaya, I. Yu.,Gatilov, Yu. V.,Kron, A. A.,Barkhash, V. A.
, p. 1877 - 1890 (2007/10/02)
Experimental evidence is offered for the first time to support the scheme of the cationoid molecular rearrangements of pseudodamascones and geranate esters with the detection of intermediate carbocations.Comparison of the behaviour of isomeric pseudodamascones and pseudoionones in superacids revealed the effect of structural modification on the mechanisms of the cationoid rearrangements of these conjugated ketones.In the case of geranate esters, the effect of the configuration of a conjugated double bond on the structure of the initial electrophilic cyclization products was shown.
Synthesis of (+/-)-trixagol by an electrophilic cyclization of an allylsilane
Armstrong, Rosemary J.,Weiler, Larry
, p. 2530 - 2539 (2007/10/02)
1,5-Dienes containing an allylsilane are cyclized by Lewis acids to methylenecyclohexanes.The trimethylsilyl group exerts a strong activating and directing influence on the regioselectivity of this cyclization.The monocyclic compound 10 was converted into the diterpene, (+/-)-trixagol (3).
