94397-40-7Relevant academic research and scientific papers
Bioinspired intramolecular diels-alder reaction: A rapid access to the highly-strained cyclopropane-fused polycyclic skeleton
Zhu, Shifa,Guo, Zhengjiang,Huang, Zhipeng,Jiang, Huanfeng
supporting information, p. 2425 - 2430 (2014/03/21)
A bioinsipred gold-catalyzed tandem Diels-Alder/Diels-Alder reaction of an enynal and a 1,3-diene, forming the highly-strained benzotricyclo[3.2.1.0 2,7]octane skeleton, was reported. In contrast, a Diels-Alder/Friedel-Crafts tandem reaction occurred instead when silver salts were used as the catalyst. Although both reactions experienced the similar Diels-Alder reaction of a pyrylium intermediate with a 1,3-diene, they have different reaction mechanisms. The former proceeded with a stepwise Diels-Alder reaction, while the latter one with a concerted one. Mother nature knows best! A gold-catalyzed reaction of enynals and 1,3-dienes, giving rapid access to the highly strained benzotricyclo[3.2.1.02,7]octane skeleton, is reported (see scheme; QMD=quinodimethane). Owing to the mild reaction conditions, excellent substrate scope, and high functional-group tolerance, this system holds potential for the construction of complex molecules with the tricyclo[3.2.1.02,7]octane skeleton. Copyright
Total synthesis of branimycin: An evolutionary approach
Enev, Valentin S.,Felzmann, Wolfgang,Gromov, Alexey,Marchart, Stefan,Mulzer, Johann
supporting information; experimental part, p. 9651 - 9668 (2012/09/21)
The first total synthesis of the macrolactone antibiotic branimycin (4) has been described. The key disconnection leads to a cis-dehydrodecalone core and a polyketide side chain which are connected via organometallic addition. The dehydrodecalone core was targeted via altogether five different approaches featuring various kinds of chiral elements and ring-closing methodology. In the end the most successful method starting from diepoxynaphthalene 109 was chosen to carry on with the synthesis. Thus the oxygen functions and carbon appendages were introduced via organometallic desymmetrization reactions to generate epoxy ketone 107, to which vinyl iodide 11 was added after conversion into the organolithium species. The synthesis was completed by introducing the ester side chain via Michael addition and subsequent macrolactonization. Competitive approach: The first total synthesis of the macrolactone antibiotic branimycin is described (see figure). The dehydrodecalin core was targeted via five competing approaches featuring various kinds of chiral elements and ring-closing methodology. In this "Darwinian" struggle the most successful route emerged and led to the completion of the synthesis. Copyright
Highly stereoselective total synthesis of (+)-9-epi-Dictyostatin and (-)-12,13-Bis-epi-dictyostatin
Zanato, Chiara,Pignataro, Luca,Ambrosi, Andrea,Hao, Zhongyan,Trigili, Chiara,Diaz, Jose Fernando,Barasoain, Isabel,Gennari, Cesare
experimental part, p. 2643 - 2661 (2011/06/25)
The total syntheses of (+)-9-epi-dictyostatin (1a) and (-)-12,13-bis-epi- dictyostatin (1b), diastereomers of the antimitotic marine sponge-derived macrolide (-)-dictyostatin (1), were achieved by creating 11 stereogenic centers and 4stereogenic double bonds with a high level of stereocontrol. The yield for the 29-step longest linear sequence from Roche ester was 1.53 and 1.52%, respectively. The final key steps to these unnatural products were the addition of vinylzincates C10-C26 to aldehyde C1-C9 (leading surprisingly to complete stereoselectivity for the 9R-configuration in 28a and for the 9S-configuration in 12,13-bis-epimeric 28b), followed by Yamaguchi macrolactonization and global deprotection. (-)-12,13-Bis-epi-dictyostatin (1b) displayed a dramatic decrease of cytotoxicity and of the affinity toward the paclitaxel binding site of microtubules. Eleven stereogenic centers and fourstereogenic double bonds were obtained with a high level of stereocontrol in the total synthesis of (+)-9-epi-dictyostatin and(-)-12,13-bis-epi-dictyostatin, diastereomers of the antimitotic marine sponge-derived macrolide (-)-dictyostatin.
The Reaction of Polyhalides with Allylsilanes Catalyzed by Copper(I) Chloride
Mitani, Michiharu,Hujita, Shigenori
, p. 3055 - 3060 (2007/10/03)
Allyltrimethylsilane reacted with polyhalogen compounds in the presence of copper species, such as copper(I) chloride, copper(II) chloride or metallic copper, to form polyhalo compounds containing an allyl group. Other allylsilane derivatives than allyltrimethylsilane were also subjected to a reaction with carbon tetrachloride. 3-Chloro- or 3-bromo-3-trimethylsilyl-1-propene gave 4,4,4-trichloro-1-trimethylsilyl-1-butene. Ethyl 1-trimethylsilylallyl carbonate afforded ethyl 4,4,4-trichloro-1-butenyl carbonate along with a hydrotrichloromethylation product. 2-Methyl-3-trimethylsilyl-1-propene yielded a product based on the addition of a trichloromethyl group followed by hydrogen-elimination from a 2-methyl group.
Trimethylsilylation of carbenoids generated in situ from allyl and benzyl halides
Andringa, H.,Heus-Kloos, Y.A.,Brandsma, L.
, p. C41 - C43 (2007/10/02)
Efficient procedures for the trimethylsilylation of the transient carbenoids H2C=CHCH(X)Li and PhCH(X)Li (X = Cl or Br) are described.
A NOVEL AND CONVENIENT REGIO-CONTROLLED SYNTHESIS OF α-HALOGEN-SUBSTITUTED ALLYLSILANES. STEREOSELECTIVE SYNTHESIS OF Z-ALKENYL HALIDES
Hosomi, Akira,Ando, Masatomo,Sakurai, Hideki
, p. 1385 - 1388 (2007/10/02)
α-Halogen-substituted allylsilanes, prepared conveniently by the in situ reaction of lithiated allyl halides with chlorosilane in a regio-controlled manner, react with various electrophiles to give the corresponding alkenyl halides with high Z preference.
