1530-33-2Relevant academic research and scientific papers
Photocycloaddition of biscyclopropyl alkenes to C60: An unprecedented approach toward cis-1 tricyclic-fused fullerenes
Tzirakis, Manolis D.,Alberti, Mariza N.,Orfanopoulos, Michael
, p. 3364 - 3367 (2011)
A novel, simple, and entirely regioselective tandem cycloaddition of biscyclopropyl-substituted alkenes to [60]fullerene has been revealed. This reaction affords cis-1 tricyclic-fused organofullerenes bearing the hitherto elusive 5-4-5 fused tricyclic ring system.
Remote sp3 C–H Amination of Alkenes with Nitroarenes
Xiao, Jichao,He, Yuli,Ye, Feng,Zhu, Shaolin
supporting information, p. 1645 - 1657 (2018/05/16)
Direct installation of a functional group at remote, unfunctionalized sites in an alkyl chain is a synthetically valuable but rarely reported process. The remote relay hydroarylamination of distal and proximal olefins, and of olefin isomeric mixtures, has been achieved through NiH-catalyzed alkene isomerization and sequential reductive hydroarylamination with nitroarenes. This provides an attractive approach to the direct installation of a distal arylamino group within alkyl chains. The single-step conversion of simple olefins and nitro(hetero)arenes to value-added arylamines is a practical strategy for amine synthesis as well as the remote activation of sp3 C–H bonds. The value of this transformation is further supported by the regioconvergent arylamination of isomeric mixtures of olefins. Modern organic synthesis requires more efficient strategies, such as C–H functionalization, with which to construct complex molecules from readily available chemicals. Undirected functionalization of remote aliphatic C–H bonds is a synthetically valuable but largely unknown process. Synergistic combination of metal-catalyzed chainwalking (migration of a double bond along the hydrocarbon chain, a process involving repeated migratory insertions and β-hydride eliminations) and cross-coupling chemistry offers a general approach to the remote functionalization of easily accessed unsaturated hydrocarbon substrates. In this paper, we demonstrate that direct installation of a distal arylamino group can be achieved from two common feedstock chemicals (olefins and nitroarenes) via nickel hydride chemistry. It is anticipated that the strategy could inspire the development of other remote functionalizations with different regioselectivity as well as asymmetric transformations. Zhu and colleagues describe the remote hydroamination of alkenes with nitro(hetero)arenes through nickel-catalyzed alkene isomerization and sequential reductive relay hydroamination process. Using two common feedstock chemicals, olefins and nitroaromatics, in an operationally simple procedure, this attractive protocol provides efficient and practical access to a wide range of arylamines under mild conditions.
ATP3 and MTP3: Easily Prepared Stable Perruthenate Salts for Oxidation Applications in Synthesis
Moore, Peter W.,Read, Christopher D. G.,Bernhardt, Paul V.,Williams, Craig M.
supporting information, p. 4556 - 4561 (2018/03/13)
The Ley–Griffith tetra-n-propylammonium perruthenate (TPAP) catalyst has been widely deployed by the synthesis community, mainly for the oxidation of alcohols to aldehydes and ketones, but also for a variety of other synthetic transformations (e.g. diol cleavage, isomerizations, imine formation and heterocyclic synthesis). Such popularity has been forged on broad reaction scope, functional group tolerance, mild conditions, and commercial catalyst supply. However, the mild instability of TPAP creates preparation, storage, and reaction reproducibility issues, due to unpreventable slow decomposition. In search of attributes conducive to catalyst longevity an extensive range of novel perruthenate salts were prepared. Subsequent evaluation unearthed a set of readily synthesized, bench stable, phosphonium perruthenates (ATP3 and MTP3) that mirror the reactivity of TPAP, but avoid storage decomposition issues.
A modular synthesis of teraryl-based α-helix mimetics, part 1: Synthesis of core fragments with two electronically differentiated leaving groups
Peters, Martin,Trobe, Melanie,Tan, Hao,Kleineweischede, Rolf,Breinbauer, Rolf
supporting information, p. 2442 - 2449 (2013/04/24)
Teraryl-based α-helix mimetics have proven to be useful compounds for the inhibition of protein-protein interactions (PPI). We have developed a modular and flexible approach for the synthesis of teraryl-based α-helix mimetics. Central to our strategy is the use of a benzene core unit featuring two leaving groups of differentiated reactivity in the Pd-catalyzed cross-coupling used for terphenyl assembly. With the halogen/diazonium route and the halogen/triflate route, two strategies have successfully been established. The synthesis of core building blocks with aliphatic (Ala, Val, Leu, Ile), aromatic (Phe), polar (Cys, Lys), hydrophilic (Ser, Gln), and acidic (Glu) amino acid side chains are reported. Turn on: Teraryl-based α-helix mimetics can be effectively produced by sequential Suzuki coupling of a central core fragment featuring electronically differentiated leaving groups with aryl boronic pinacol esters (see scheme; dppf=1,1′-bis(diphenylphosphino) ferrocene, DME=dimethoxyethane, Pin=pinacol, Tf=trifluoromethanesulfonyl). With a set of only 2×18 building blocks, all permutations of α-helix mimetics can be produced. Copyright
(+)- And (-)-mutisianthol: First total synthesis, absolute configuration, and antitumor activity
Bianco, Graziela G.,Ferraz, Helena M. C.,Costas, Arinice M.,Costa-Lotufo, Leticia V.,Pessoa, Claudia,De Moraes, Manoel O.,Schreins, Marcus G.,Pfaltz, Andreas,Silva Jr., Luiz F.
supporting information; experimental part, p. 2561 - 2566 (2009/09/25)
The first synthesis of the natural product (+)-mutisianthol was accomplished in 11 steps and in 21% overall yield from 2-methylanisole. The synthesis of its enantiomer was also performed in a similar overall yield. The absolute configuration of the sesquiterpene (+)-mutisianthol was assigned as (15,37?). Key steps in the route are the asymmetric hydrogenation of a nonfunctionalized olefin using chiral iridium catalysts and the ring contraction of 1,2-dihydronaphthalenes using thallium(III) or iodine(III). The target molecules show moderate activity against the human tumor cell lines SF-295, HCT-8, and MDA-MB-435.
Mechanism of the [2 + 2] photocycloaddition of fullerene C60 with styrenes
Vassilikogiannakis,Hatzimarinaki,Orfanopoulos
, p. 8180 - 8187 (2007/10/03)
Stereochemical studies on [2 + 2] photoaddition of cis-/trans-4-propenylanisole (cis-1 and trans-1) and cis-1-(p-methoxyphenyl)ethylene-2-d1 (cis-3-d1) to C60 exhibit stereospecificity in favor of the trans-2 cycloadduct in the former case and nonstereoselectivity in the latter. The observed stereoselectivity in favor of the cis-6-d3 [2 + 2] diastereomer by 12% in the case of the photochemical addition of (E)-1-(p-methoxyphenyl)-2-methyl-prop-1-ene-3,3,3-d3 (trans-5-d3) to C60 is attributed to a steric kinetic isotope effect (k(H)/k(D) = 0.78). The loss of stereochemistry in the cyclobutane ring excludes a concerted addition and is consistent with a stepwise mechanism. Intermolecular secondary kinetic isotope effects of the [2 + 2] photocycloaddition of 3-d0 vs 3-d1, and 3-d6 as well as 5-d0 vs 5-d1, and 5-d6 to C60 were also measured. The intermolecular competition due to deuterium substitution of both vinylic hydrogens at the β-carbon of 3 exhibits a substantial inverse α-secondary isotope effect k(H)/k(D) = 0.83 (per deuterium). Substitution with deuterium at both vinylic methyl groups of 5 yields a small inverse k(H)/k(D) = 0.94. These results are consistent with the formation of an open intermediate in the rate-determining step.
Cyclialkylation of arylalkyl epoxides with solid acid catalysts
Elings, Jacob A.,Downing, Roger S.,Sheldon, Roger A.
, p. 837 - 846 (2007/10/03)
Solid acids, such as zeolites and clays, catalyse the intramolecular hydroxyalkylation (cyclialkylation) of several arylalkyl epoxides in moderate to excellent conversions and selectivities. The use of solid acids in these cyclialkylations provides a cleaner, better alternative to conventional Lewis and Bronsted acids, enabling a more facile workup of reaction mixtures and, in several cases, better selectivities.
Pheromone Synthesis, CXXXI Synthesis of the Four Stereoisomers of 6,10,13-Trimethyl-1-tetradecanol, Aggregation Pheromone of Predatory Stink Bug, Stiretrus anchorago
Mori, Kenji,Wu, Jiang
, p. 783 - 788 (2007/10/02)
The synthesis of the four stereoisomers of 6,10,13-trimethyl-1-tetradecanol (1a), the male-produced aggregation pheromone of the predatory stink bug Stiretrus anchorago, was achieved by starting from (R)-citronellol (2a), methyl (R)- or (S)-3-hydroxy-2-methylpropanoate (10) and 4-chloro-1-butanol (12a). - Key Words: Grignard coupling / Phenyl sulfone, alkylation of / Pheromone, enantiomerically pure / Stiretrus anchorago / 1-Tetradecanol, 6,10,13-trimethyl- / Sulfones
Thermal rearrangements of allenes. Synthesis and mechanism of cycloaromatization of π and heteroatom bridged diallenes
Braverman, Samuel,Duar, Ytzhak
, p. 5830 - 5837 (2007/10/02)
The synthesis and thermal rearrangement of several π and heteroatom bridged diallenes has been investigated. o-Diallenylbenzenes 5, 14, 24 and bis(γ,γ-dimethylallenyl) ether 8 were prepared by addition of dibromocarbene to the corresponding divinyl precursor, followed by treatment of the resulting dibromocyclopropane derivative with methyllithium. Bis(γ,γ-dimethylallenyl) sulfide 10 was generated by reaction of (γ,γ-dimethylallenyl)lithium with sulfur dichloride, while the corresponding selenides 12 and 16 were synthesized by an SN2′ reaction of sodium selenide with α,α-dimethylpropargyl bromide. All diallenes prepared display a remarkable thermal reactivity and undergo a facile cycloaromatization. Gentle heating of diallenes 5, 14, 12, and 16 gave the naphthalene derivatives 6 and 15 and selenophene derivatives 13 and 17, respectively, in practically quantitative yields. Diallenes 8, 10, and 24 underwent spontaneous cyclization during preparation yielding furan 9, thiophene 11, and naphtho[b]cyclobutane 25, respectively. A kinetic study of the rearrangement and measurement of the kinetic isotope effect using diallenes 5, 14, 12, and 16, revealed that the cyclization is a two-step process. The first and rate-determining step is an electrocyclic reaction yielding as intermediates ω-xylylenes 20 and 21, while the second and more rapid step entails a [1,5]hydrogen transfer.
