86990-92-3Relevant academic research and scientific papers
Studies towards the total synthesis of cruentaren A and B: Stereoselective synthesis of fragments C1-C11, C12-C22 and C23-C28
Ganganna, Bogonda,Srihari, Pabbaraja,Yadav, Jhillu Singh
supporting information, p. 2685 - 2689 (2017/06/23)
A convergent and stereoselective approach for the synthesis of C1-C11, C12-C22, and C23-C28 fragments of cytotoxic natural products cruentaren A and B are accomplished. Highlights of the strategy include a Sharpless epoxidation followed by a regioselective opening of epoxide to generate anti and syn-stereochemistry at C9-C10 and C15-C16, an Alder-Rickert reaction between a 1,5-dimethoxy-1,4-cyclohexadiene and dienophile to construct the aromatic ring, and a lithium-mediated aldol reaction to install the C17-C18 anti-stereochemistry. The synthesis of C1-C11 and C12-C22 fragments proceed with a longest linear sequence of 10 and 17 steps from commercially available 2-butyne-1,4-diol and cis-2-butene-1,4-diol respectively.
Total synthesis and evaluation of cytostatin, its C10-C11 diastereomers, and additional key analogues: Impact on PP2A inhibition
Lawhorn, Brian G.,Boga, Sobhana B.,Wolkenberg, Scott E.,Colby, David A.,Gauss, Carla-Maria,Swingle, Mark R.,Amable, Lauren,Honkanen, Richard E.,Boger, Dale L.
, p. 16720 - 16732 (2007/10/03)
The total synthesis of cytostatin, an antitumor agent belonging to the fostriecin family of natural products, is described in full detail. The convergent approach relied on a key epoxide-opening reaction to join the two stereotriad units and a single-step
Synthetic studies on bafilomycin A1: Stereoselective synthesis of the C12-C17 fragment and its coupling with the C 1-C11 subunit
Quéron, Emmanuelle,Lett, Robert
, p. 4533 - 4537 (2007/10/03)
Stereoselective addition of (E)-1-lithio-2-tributylstannylethylene on a chiral cyclic di-t-butylsilyleneketal C14-C17 aldehyde afforded the required Felkin-Anh adduct for the synthesis of the C 12-C17 fragment of bafilomycin A1, the configuration of which was assigned unambiguously. After appropriate coupling with the enantiopure C1-C11 fragment, the C 12-C17 subunit obtained here can be used for the study of the 16-membered macrolide formation either by an acyl activation or an intramolecular Stille reaction. Intermolecular esterification of the 15-OH with an acyl activation of the carboxylic acid of the C1-C11 fragment, in modified Yamaguchi's conditions, affords here an intermediate for examining an intramolecular Stille coupling.
Highly diastereoselective anti-Aldol reactions utilizing the titanium enolate of cis-2-arylsulfonamido-1-acenaphthenyl propionate
Ghosh, Arun K.,Kim, Jae-Hun
, p. 1063 - 1066 (2007/10/03)
(Matrix presented) anti-Aldol reaction of Ti-enolate derived from cis-2-arylsulfonamido-1-acenaphthenyl propionate with representative aldehydes proceeded in excellent yield with high diastereoselectivity. Both enantiomers of cis-2-amino-1-acenaphthenol w
Regioselective Alkyl and Alkynyl Substitution Reactions of Epoxy Alcohols by the Use of Organoaluminum Ate Complexes: Regiochemical Reversal of Nucleophilic Substitution Reactions
Sasaki, Minoru,Tanino, Keiji,Miyashita, Masaaki
, p. 1765 - 1767 (2007/10/03)
(matrix presented) Unprecedented nucleophilic substitution reactions of 2,3-epoxy-1-alkanols with alkyl- and alkynylaluminum ate complexes have been studied and demonstrated to occur at the C2 position with extremely high stereoselectivity, i.e., with exa
Anti-Markovnikov opening of trisubstituted epoxy alcohols: Application in the synthesis of 2-methyl-1,3-diols
Chakraborty, Tushar K.,Dutta, Shantanu
, p. 1257 - 1259 (2007/10/03)
2-Methyl-1,3-diols are synthesized by regioselectively opening trisubstituted epoxides, prepared from 2-methylbut-2-en-1-ols at the more substituted carbon using Cp2TiCl-cyclohexa-1,4-diene.
Synthetic studies on oligomycins. Synthesis of the oligomycin B spiroketal and polypropionate portions
Nakata,Ishiyama,Akamatsu,Hirose,Maruoka,Suzuki,Tatsuta
, p. 967 - 989 (2007/10/02)
The oligomycin B spiroketal portion, [2S,2(2R),3S,6R,8S,8(3R),9S,10R,11S]-2-[2-(t-butyldiphenylsilyloxy)pro pyl]-8-[3-(hydroxymethyl)pentyl]-3,9,11-trimethyl-1,7-dioxaspiro[5,5]u ndecane-5,10-diol (2), and polypropionate portion, ethyl (2E,4S,5R,6R,7S,8S,9R,10S,12R,13S,14R,16E)-5-(t-butyldimethylsilyloxy) -7,9-(isopropylidenedioxy)-12,13-(4-methoxybenzylidenedioxy)4,6,8,10,1 2,14-hexamethyl-11-oxo-18-phenylsulfonyloctadeca-2,16-dienoate (3), have been synthesized. The C19-C21 Wittig salt, [(2S,3R)-2-ethyl-3,4-isopropylidenedioxy)butyl]triphenylphosphonium iodide (6), prepared from 2-butene-1,4-diol via Sharpless epoxidation, was coupled with the C22-C27 aldehyde, benzyl 2,4-dideoxy-3-O-(4-methoxybenzyl)-2,4-di-C-methyl-α,β-L-galacto-hexo dialdopyranoside-(1,5) (7), prepared from (Z)-2-butene-1,4-diol via Sharpless epoxidation and the Brown's crotylboration. The resulting coupling product was transformed to the C19-C27 lactone, [3S,4R,5R,6S,6(3R,4R)]-6-[3-ethyl-4,5-(isopropylidenedioxy)pentyl]-4-( 4-methoxybenzyloxy)-3,5-dimethyl-3,4,5,6-tetrahydro-2H-pyran-2-one (4). The C28-C34 organostannane compound, (2R,4S,5S,7RS)-2-(t-butyldiphenylsilyloxy)-5-methyl-7-(tributylstannyl )-4-(triethylsilyloxy)-7-[(2-trimethylsilylethoxy)methoxy]heptane (5b), was prepared from (R)-methyl 3-hydroxybutyrate via the Brown's crotylboration and the Still's stannylation. After lithiation of 5b with butyllithium, the resulting α-alkoxy organolithium compound was coupled with 4 and the product was converted to the C19-C34 spiroketal, [2S,2(2R),3S,6R,8S,8(3R,4R),9S,10R,11S]-2-[2-t-butyldiphenylsilyloxy)p ropyl]-8-[3-ethyl-4,5-(isopropylidenedioxy)pentyl]-10-(4-methoxybenzyl oxy)-3,9,11-trimethyl-1,7-dioxaspiro[5,5]undecan-5-ol (37). The synthetic 2, derived fron 37, was identical to the oligomycins (A, B, C mixture) degradation product in all respects, which elucidates the absolute stereochemistry of oligomycin B (1b). The C3-C9 aldehyde, (2-trimethylsilylethoxy)methyl 2,4,5-trideoxy-3-O-(4-methoxybenzyl)-2,4,6-tri-C-methyl-D-glycero-α-L -ido-heptodialdopyranoside-(1,5) (9), was prepared from (2S)-3-(t-butyldimethylsilyloxy)-2-methylpropanal via Keck's crotylstannane addition and Brown's crotylboration. The aldol coupling between the zinc enolate of the C10-C16 ketone, t-butyldimethylsilyl 2,3,7,8-tetradeoxy-4-O-(4-methoxybenzyl)-3,5-di-C-methyl-α-L-xylo-oct opyranosid-6-ulose (10), prepared from methyl (R)-(+)-lactate via Brown's crotylboration and a metallated methoxyallene addition, and aldehyde 9 gave the C8-C9 syn, C9-C10 syn product, which was transformed to the oligomycin B polypropionate portion 3 through elongation of the C1-C2 and C17-C18 carbon units.
Synthetic Studies on Oligomycins. Enantiospecific Synthesis of the Oligomycin B Spiroketal Portion and Establishment of the Absolute Stereochemistry of Oligomycin B
Nakata, Masaya,Ishiyama, Takashi,Hirose, Youichi,Maruoka, Hiroshi,Tatsuta, Kuniaki
, p. 8439 - 8442 (2007/10/02)
The enantiospecific synthesis of the oligomycin B degradation product 2, corresponding to the C19-C34 spiroketal portion, has been achieved by sequential coupling of the C19-C21, C22-C27, and C28-C34 subunits, establishing the absolute stereochemistry of oligomycin B.
Isomer Selectivity in Stereocontrolled Payne Rearrangement-epoxide Cleavage of 2,3-Epoxy Alcohols in Aprotic Solvents: Application to an Enantioselective Total Synthesis of (+)-exo-Brevicomin
Page, Philip C. Bulman,Rayner, Christopher M.,Sutherland, Ian O.
, p. 1375 - 1382 (2007/10/02)
Organo-copper and -cuprate reagents may be used to trap the more reactive epoxy alkoxide isomer in a Lewis acid-catalysed Payne rearrangement process.This methodology has been used as the key step in a five-step enantioselective total synthesis of (+)-exo
A NEW SYNTHESIS OF (-)-Α-MULTISTRIATIN, THE PHEROMONE OF THE SMALLER EUROPEAN ELM BARK BEETLE
Mori, Kenji,Seu, Young-Bae
, p. 1035 - 1038 (2007/10/02)
(-)-Α-Multistriatinoctane> was synthesized from (Z)-2-butene-1,4-diol monobenzyl ether by employing the sharpless asymmetric epoxidation and the regioselective epoxide cleavage with Me3Al as the k
