53952-98-0Relevant academic research and scientific papers
Copper-Catalyzed Tandem Cross-Coupling and Alkynylogous Aldol Reaction: Access to Chiral Exocyclic α-Allenols
Xu, Guangyang,Wang, Zhen,Shao, Ying,Sun, Jiangtao
, p. 5175 - 5179 (2021/07/19)
An enantioselective copper-catalyzed tandem cross-coupling/alkynylogous aldol reaction has been developed. The tetrasubstituted allenoates containing both central and axial chirality have been obtained in moderate to good yields and excellent enantio-and
Intermolecular Dehydrative Coupling and Intramolecular Cyclization of Ruthenium Vinylidene Complexes Formed from Aromatic Propynes Containing Carbonyl Functionalities
Chia, Pi-Yeh,Kuo, Cheng-Chen,Huang, Shou-Ling,Liu, Yi-Hong,Liu, Ling-Kang,Lin, Ying-Chih
, p. 3885 - 3894 (2018/11/10)
A remarkable intermolecular dehydrative coupling reaction with the formation of a C?C bond was found for the vinylidene complex 2 a, yielding the dinuclear bisvinylidene complex 4 a. Complex 2 a containing 1-hydroxyindan moiety was first formed from the reaction of o-propynyl benzaldehyde 1 a with [Ru]–Cl ([Ru]=Cp(PPh3)2Ru) by a cyclization process. For analogous aldehyde 1 b containing an additional 1,3-dioxolane group on the aryl ring, similar intermolecular coupling yields the dinuclear bisvinylidene complex 4 b. However, the fluoro group on the aryl ring in aldehyde 1 c inhibits the coupling reaction, giving only the vinylidene complex 2 c. For the reactions of [Ru]–Cl in MeOH with compounds 1 f, 1 g and 1 h, each with a ketone functionality, cyclization gives vinylidene complexes 2 f, 2 g and 2 h, respectively. However, no similar intermolecular coupling was observed, instead, the intramolecular dehydration yields 8 f, 8 g and 8 h, respectively. In CDCl3, catalytic cyclization is observed for the o-propynylphenyl ketone 1 h with [Ru]–Cl at 50 °C giving the isochromene products 14 h. Furthermore, treatment of the o-propynylaryl α,β-unsaturated ketones 1 k–m and 1 n with [Ru]–Cl in MeOH affords the corresponding vinylidene complexes 10 k–m and 11 n each with 1-benzosuberone moiety in the presence of NH4PF6. These intramolecular cyclization products were formed by the addition of Cβ onto the terminal carbon of the alkene moiety. All these reaction products were characterized by spectroscopic methods. In addition, structures of complexes 4 a, and 10 l were confirmed by single crystal X-ray diffraction analysis.
Structure-property relationship of naphthalene based donor-π-acceptor organic dyes for dye-sensitized solar cells: Remarkable improvement of open-circuit photovoltage
Yang, Fan,Jin, Tienan,Yamamoto, Yoshinori,Akhtaruzzaman, Md.,Islam, Ashraful,Qin, Chuanjiang,Han, Liyuan,El-Shafei, Ahmed,Alamry, Khalid A.,Kosa, Samia A.,Hussein, Mahmoud A.,Asiri, Abdullah Mohamed
supporting information, p. 22550 - 22557,8 (2020/09/15)
Four new donor-π-acceptor organic dyes (YF01-04), containing naphthalene-substituted amines as an electron donor and cyanoacrylic acid as an electron acceptor, were designed and synthesized, and their photophysical properties and dye-sensitized solar cells (DSCs) performances were characterized. Dyes YF02 and YF04, with 2,6-disubstituted naphthalene frameworks, were superior than their analog dyes YF03 and YF01, having 1,2-disubstituted naphthalene moiety, in incident-photo-to-current conversion efficiency (IPCE) and total solar-to-electric conversion efficiency (η). The DSCs based on YF02, comprised of diphenylamine moiety as the donor, produced the highest η of 5.29% compared to 4.03% of the analog dye YF04, which has pyrrolidine as the donor. Remarkably, a high open-circuit photovoltage (V oc) of 0.799-0.807 V was achieved in the cases of YF02-03, which have diphenylamine-donors. To better understand the structure-property relationship for DSCs application, molecular modelling was performed on YF01-04 and vertical electronic excitations were calculated using long-range corrected energy functional WB97XD and CAM-B3LYP at the basis set level DGDZVP, which were in excellent agreement with the experimental results. Moreover, the equilibrium molecular geometries of dyes YF01-04 were calculated at the density function theory (DFT) level using the hybrid energy functional B3LYP and basis set DGDZVP. The torsion angles () between the naphthalene moiety and diphenylamine donor in YF02 and YF03 were more twisted than that of the pyrrolidine-donor dyes YF01 and YF04, precluding efficient intermolecular π-π charge transfer, which translated into high Voc. Compared to the reference dye TA-St-CA, which is based on diphenylamine as an electron donor linked to a phenyl ring, YF02 achieved higher Voc, which indicated that naphthalene substituted with diphenylamine is more efficient in retarding charge recombinations.
Intramolecular hydroalkoxylation/cyclization of alkynyl alcohols mediated by lanthanide catalysts. Scope and reaction mechanism
Seo, SungYong,Yu, Xianghua,Marks, Tobin J.
experimental part, p. 263 - 276 (2009/06/28)
Lanthanide-organic complexes of the general type Ln[N(SiMe 3)2]3 (Ln = La, Sm, Y, Lu) serve as effective precatalysts for the rapid, exoselective, and highly regioselective intramolecular hydroalkoxy- lation/cyclization of primary and secondary alkynyl alcohols to yield the corresponding exocyclic enol ethers. Conversions arehighly selective with products distinctly different from those generall y produced by conventional transition metal catalysts, and turnover frequencies as high as 52.8 h-1 at 25 °C are observed. The rates of terminal alkynl alcohol hydroalkoxylation/cyclization are significantly more rapid than those of internal alkynyl alcohols, arguing that steric demands dominate the cyclization transition state. The hydroalkoxylation/cyclization of internal alkynyl alcohols affords excellent E -selectivity. The hydroalkoxylation/ cyclization of the SiMe3-terminated internal alkynyl alcohols reveals interesting product profiles which include the desired exocyclic ether, a SiMe3-eliminatedexocyclic ether, and the SiMe3-O- functionalized substrate. The rate law for alkynyl alcohol hydroalkoxylation/ cyclization is first -order in [catalyst] and zero-order in [alkynyl alcohol], as observed inthe intramolecular hydroamination/cyclization of aminoalkenes, aminoalk ynes, and aminoallenes. An ROH/ROD kinetic isotope effect of 0.95(0.03) is observed for hydroalkoxy- lation/cyclization. These mechanistic data implicate turnover-limiting insertion of C-C unsaturation into the Ln-O bond, involving a highly organized transition state, with subsequent, rapid Ln-C protonolysis.
Acceleration effect of an allylic hydroxy group on ring-closing enyne metathesis of terminal alkynes: Scope, application, and mechanistic insights
Imahori, Tatsushi,Ojima, Hidetomo,Yoshimura, Yuichi,Takahata, Hiroki
supporting information; experimental part, p. 10762 - 10771 (2009/12/01)
An interesting acceleration effect of an allylic hydroxy group on ring-closing enyne metathesis has been found. Ring-closing enyne metathesis of terminal alkynes possessing an allylic hydroxy group proceeded smoothly without the ethylene atmosphere generally necessary to promote the reaction. The synthesis of (+)-isofagomine with the aid of this efficient reaction has been demonstrated. Mechanistic studies of the acceleration effect were also carried out. Results of NMR studies suggested that the reaction proceeded via an "ene-then-yne" pathway. Kinetic studies indicated switching of the rate-determining step as a consequence of the presence of an allylic hydroxy group. These results suggest acceleration of the reentry step of Ru-carbene species by the allylic hydroxy group.
Catalytic one-pot synthesis of cyclic amidines by virtue of tandem reactions involving intramolecular hydroamination under mild conditions
Chang, Sukbok,Lee, Minjae,Jung, Doo Young,Yoo, Eun Jeong,Cho, Seung Hwan,Han, Sun Kyu
, p. 12366 - 12367 (2007/10/03)
A new synthetic methodology for the generation of cyclic amidines has been developed by the reaction of 1,n-aminoalkynes with electron-deficient azides using a ruthenium catalyst at ambient temperature. The reaction proceeds most likely via a tandem sequence of intramolecular hydroamination of aminoalkynes, cycloaddition of azides with the resulting enamines, and rearrangement of triazoline intermediates. It demonstrates, as the proof-of-principle, that an equilibria cascade sequence can be favorably driven by an irreversible step, thus enabling a facile one-pot synthetic route to deliver molecular complexity under unprecedented mild conditions without relying on the traditional linear approaches. Copyright
The synthesis of annulated azepin-3-one derivatives from 1,3,4-pentatrienyl nitrones by a heterocyclization - Rearrangement sequence
Knobloch, Karin,Keller, Manfred,Eberbach, Wolfgang
, p. 3313 - 3332 (2007/10/03)
Treatment of various o-propargylaryl nitrones of type 6 with potassium hydroxide or sodium methoxide in methanol at room temperature provides 1,2-dihydro[c]benzazepin-3-ones 9. The high product yields and the ease of the reactions under surprisingly mild conditions are particularly intriguing in view of the complex mechanistic pathway involved in the overall transformation. A mechanism based on a multistep rearrangement is proposed, involving conjugated allene nitrones of type 13 as precursors of a 1,7-dipolar cyclization process that is followed by further bond reorganizations, with cyclopropanones 16 as key intermediates. In agreement with the allene formation is the fact that the same transformation can be achieved with the triple bond isomers 12 and 37, which contain terminal alkyl groups. The intermediacy of cyclopropanones 16 is supported by the competing formation of the isoindoles 20 as minor products. On treatment of dihydronaphtho-annulated nitrones 30 with base, formation of the azepinones 31 as the main products is also accompanied by that of the isomeric isoindoles 32. Some selective C=O and C=C hydrogenation reactions, together with conversions into the thioketone 42 and the vinyl bromide 9p, have been demonstrated with representative examples of 9.
Dihydro[c]benzazepin-3-ones via conjugated nitrone-allene precursors
Knobloch, Karin,Eberbach, Wolfgang
, p. 1117 - 1120 (2007/10/03)
Treatment of o-propargylaryl nitrones with base provided 1,2-dihydro[c]benzazepin-3-ones in good yields. The straightforward transformation is explained on the basis of a multistep rearrangement involving conjugated allene-nitrones as precursors of a 1,7-dipolar electrocyclization process that is followed by further bond reorganizations.
