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1.
Hydroaminomethylation Beyond Carbonylation: Allene–Imine Reductive Coupling by Ruthenium‐Catalyzed Transfer Hydrogenation 下载免费PDF全文
Susumu Oda Brannon Sam Prof. Michael J. Krische 《Angewandte Chemie (International ed. in English)》2015,54(29):8525-8528
Ruthenium(II)‐catalyzed hydrogen transfer from 2‐propanol mediates reductive coupling of 1,1‐disubstituted allenes with formaldimines with complete branch‐regioselectivity, thus representing a new method for hydroaminomethylation beyond classical hydroformylation/reductive amination. 相似文献
2.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(7):1929-1933
An unprecedented highly regio‐ and enantioselective rhodium‐catalyzed addition of 1,3‐diketones to terminal and 1,1‐disubstituted allenes furnishing asymmetric tertiary and quaternary all‐carbon centers is reported. By applying a RhI/phosphoramidite/TFA catalytic system under mild conditions, the desired chiral branched α‐allylated 1,3‐diketones could be obtained in good to excellent yields, with perfect regioselectivity and in high enantioselectivity. The reaction shows a broad functional‐group tolerance on both reaction partners highlighting its synthetic potential. 相似文献
3.
U. Amrutha Beneesh P.Babu Sreedharan Prathapan 《Journal of heterocyclic chemistry》2019,56(12):3236-3243
In the cycloaddition reaction between fluorenone N‐aryl nitrones and 1,1‐disubstituted allenes, the initially formed cycloadduct underwent facile [1,3] shift to give 1′‐phenylspiro[fluorene‐9,2′‐pyrrolidin]‐4′‐ones. Although 1′‐phenylspiro[fluorene‐9,2′‐pyrrolidin]‐4′‐ones are stable in solid state, a few of them underwent facile aerial oxidation in solution to give the corresponding 1′‐phenylspiro[fluorene‐9,2′‐pyrrolidine]‐4′,5′‐diones in excellent overall yields. 相似文献
4.
Z‐Selective Hydrothiolation of Racemic 1,3‐Disubstituted Allenes: An Atom‐Economic Rhodium‐Catalyzed Dynamic Kinetic Resolution 下载免费PDF全文
Adrian B. Pritzius Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2015,54(52):15818-15822
A Z‐selective rhodium‐catalyzed hydrothiolation of 1,3‐disubstituted allenes and subsequent oxidation towards the corresponding allylic sulfones is described. Using the bidentate 1,4‐bis(diphenylphosphino)butane (dppb) ligand, Z/E‐selectivities up to >99:1 were obtained. The highly atom‐economic desymmetrization reaction tolerates functionalized aromatic and aliphatic thiols. Additionally, a variety of symmetric internal allenes, as well as unsymmetrically disubstituted substrates were well tolerated, thus resulting in high regioselectivities. Starting from chiral but racemic 1,3‐disubstituted allenes a dynamic kinetic resolution (DKR) could be achieved by applying (S,S)‐Me‐DuPhos as the chiral ligand. The desired Z‐allylic sulfones were obtained in high yields and enantioselectivities up to 96 % ee. 相似文献
5.
Ruthenium‐Catalyzed CC Coupling of Fluorinated Alcohols with Allenes: Dehydrogenation at the Energetic Limit of β‐Hydride Elimination 下载免费PDF全文
Brannon Sam Tom Luong Prof. Michael J. Krische 《Angewandte Chemie (International ed. in English)》2015,54(18):5465-5469
Ruthenium(II) complexes catalyze the C? C coupling of 1,1‐disubstituted allenes and fluorinated alcohols to form homoallylic alcohols bearing all‐carbon quaternary centers with good to complete levels of diastereoselectivity. Whereas fluorinated alcohols are relatively abundant and tractable, the corresponding aldehydes are often not commercially available because of their instability. 相似文献
6.
Brannon Sam Tom Luong Michael J. Krische 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(18):5555-5559
Ruthenium(II) complexes catalyze the C C coupling of 1,1‐disubstituted allenes and fluorinated alcohols to form homoallylic alcohols bearing all‐carbon quaternary centers with good to complete levels of diastereoselectivity. Whereas fluorinated alcohols are relatively abundant and tractable, the corresponding aldehydes are often not commercially available because of their instability. 相似文献
7.
Zachary D. Miller Ruth Dorel Prof. John Montgomery 《Angewandte Chemie (International ed. in English)》2015,54(31):9088-9091
Methods for the highly stereoselective and regiodivergent hydrosilylation of 1,3‐disubstituted allenes have been developed. The synthesis of E allylsilanes is accomplished with palladium NHC catalysts, and trisubstituted Z alkenylsilanes are accessed with nickel NHC catalysts. Unsymmetrically substituted allenes are well tolerated with nickel catalysis and afford Z alkenylsilanes. Evidence for a plausible mechanism was obtained through an isotopic double‐labeling crossover study. 相似文献
8.
《Journal of heterocyclic chemistry》2017,54(2):1430-1436
A chiral cyclic carbonate, 4‐vinyl‐1,3‐dioxolan‐2‐one was used as racemic substrate in asymmetric hydroformylation. The catalysts were formed in situ from “pre‐formed” PtCl2(diphosphine) and tin(II) chloride. (2S,4S )‐2,4‐Bis(diphenylphosphinopentane ((S,S )‐BDPP)), (S,S )‐2,3‐O‐izopropylidine‐2,3‐dihydroxy‐1,4‐bis(diphenylphosphino)butane ((S,S )‐DIOP)), and (R )‐2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl ((R )‐BINAP)) were used as optically active diphosphine ligands. The platinum‐containing catalytic systems provided surprisingly high activity. The hydroformylation selectivities of up to 97% were accompanied by perfect regioselectivity towards the dioxolane‐based linear aldehyde. The enantiomeric composition of all components in the reaction mixture was determined and followed throughout the reaction. The unreacted 4‐vinyl‐1,3‐dioxolan‐2‐one was recovered in optically active form. The kinetic resolution was rationalized using the enantiomeric composition of the substrate and the products. 相似文献
9.
Palladium‐Catalyzed Decarboxylative γ‐Arylation for the Synthesis of Tetrasubstituted Chiral Allenes
Ina Scheipers Christian Mück‐Lichtenfeld Armido Studer 《Angewandte Chemie (International ed. in English)》2019,58(20):6545-6548
An enantiospecific palladium‐catalyzed decarboxylative coupling of acyclic β,γ‐alkynoic acids with various aryl iodides to chiral tetrasubstituted allenes is described. The coupling reaction comprises a decarboxylative γ‐palladation of α,α‐disubstituted carboxylic acids to provide the tetrasubstituted allenes with complete point‐to‐axial chirality transfer in excellent yields. 相似文献
10.
The four porphodimethene isomers, 5,10‐ and 5,15‐disubstituted, have been synthesized in a one‐pot reaction by the Lindsey protocol. Three of them have been characterized by X‐ray crystallography. Structures show that two of them are 5,15‐porphodimethenes: one is syn‐equatorial, another is anti‐configuration; the third one is 5,10‐porphodimethene. In the 5,10‐porphodimethene, the tripyrrane subunit remains planar conformation. 1H NMR and UV‐vis spectra have also been characterized. Both spectra reveal remarkable difference between 5,10‐ and 5,15‐disubstituted isomers. 相似文献
11.
Walid Fathalla Pavel Pazdera Michal ajan Jaromír Marek 《Journal of heterocyclic chemistry》2002,39(6):1145-1152
Regioselective reactions of morpholine‐1‐carbothioic acid (2‐phenyl‐3H‐quinazolin‐4‐ylidene) amide ( 1 ) with electrophiles and nucleophiles were studied. The compound ( 1 ) reacts with alkyl halides in basic medium to afford S‐substituted isothiourea derivatives, with amines to give 1,1‐disubstituted‐3‐(2‐phenyl‐3H‐quinazolin‐4‐ylidene) thioureas and l‐substituted‐3‐(2‐phenyl‐quinazolin‐4‐yl) thioureas via transami‐nation reaction. The reaction of ( 1 ) with amines in the presence of H2O2 provided N4‐disubstituted‐N'4‐(2‐phenylquinazolin‐4‐yl)morpholin‐4‐carboximidamide via oxidative desulfurization. Estimation of reactivity sites on ( 1 ) was supported using the ab initio (HF/6‐31G**) quantum chemistry calculations. The ir, 1H nmr, 13C nmr, mass spectroscopy and x‐ray identified the isolated products. 相似文献
12.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(36):11030-11033
The first total synthesis of the tetracyclic sesquiterpenoid (+)‐dendrowardol C is described. It relies on an intramolecular aldol reaction to forge the central bicyclic scaffold and subsequent cyclobutane formation by cyclization of a γ‐triflyloxy ketone. Key is the treatment of the latter with lithium naphthalenide. Finally, the diastereoselective hydroboration of a 1,1‐disubstituted double bond is enabled by a chiral CoI catalyst. 相似文献
13.
Junyu Dong Tianbin Li Chuan Dai Wen Weng Xinghua Xue Yuyu Zhang Qingle Zeng 《应用有机金属化学》2013,27(6):337-340
A straightforward, protecting‐group‐free protocol for the synthesis of chiral 6‐substituted and 6,6’‐disubstituted binols (binol = 1,1’‐bi‐2‐naphthol) by palladium‐catalyzed hydroxylation, C–N and C–O coupling of chiral 6‐bromo‐ and 6,6’ ‐dibromo‐1,1’‐binaphthols is developed. The protecting group free palladium‐catalyzed hydroxylation, C–O and C–N cross‐coupling protocol affords a straightforward and general method for the synthesis of chiral 6‐substituted and 6,6’‐disubstituted binols with good yields, avoiding the tedious procedures of introduction and removal of protecting groups. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
14.
Junxian Yang Zheng Wang Zeyuan He Guofeng Li Liang Hong Wangsheng Sun Rui Wang 《Angewandte Chemie (International ed. in English)》2020,59(2):642-647
The first asymmetric synthesis of tetrasubstituted α‐amino allenoates by a chiral phosphoric acid catalyzed dearomative γ‐addition reaction of 2,3‐disubstituted indoles to β,γ‐alkynyl‐α‐imino esters is reported. This method provides access to a series of highly functionalized tetrasubstituted allenes featuring quaternary stereocenters in high yields, and with excellent regio‐, diastereo‐, and enantioselectivities under mild conditions without by‐product formation. Representative large‐scale reactions and diverse transformations of the products into various scaffolds with potential biological activities render are also disclosed. The mechanism of the reaction was elucidated by control reactions and DFT calculations. 相似文献
15.
Rhodium(III)‐Catalyzed [4+1] Annulation of Aromatic and Vinylic Carboxylic Acids with Allenes: An Efficient Method Towards Vinyl‐Substituted Phthalides and 2‐Furanones 下载免费PDF全文
Dr. Parthasarathy Gandeepan Dr. Pachaiyappan Rajamalli Prof. Dr. Chien‐Hong Cheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(25):9198-9203
A highly regio‐ and stereoselective synthesis of 3,3‐disubstituted phthalides from aryl carboxylic acids and allenes using a rhodium(III) catalyst has been demonstrated. The reaction features broad functional group tolerance and provides a simple and straightforward route to the synthesis of various 3‐vinyl‐substituted phthalides. Furthermore, the catalytic reaction can also be applied to the synthesis of biologically active 5‐vinyl‐substituted 2‐furanones from α,β‐unsaturated carboxylic acids and allenes. The reactions proceed through a carboxylate‐assisted ortho‐C?H activation and [4+1] annulation. The preliminary mechanistic studies suggest that a C?H cleavage is the rate‐determining step. 相似文献
16.
In the title compound, catena‐poly[[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[1,1′‐biphenyl]‐4,4′‐dicarboxylato‐[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]], [Zn2(C14H8O4)Cl2(C26H22N4O2)3]n, the ZnII centre is four‐coordinate and approximately tetrahedral, bonding to one carboxylate O atom from a bidentate bridging dianionic [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand, to two pyridine N atoms from two N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide ligands and to one chloride ligand. The pyridyl ligands exhibit bidentate bridging and monodentate terminal coordination modes. The bidentate bridging pyridyl ligand and the bridging [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand both lie on special positions, with inversion centres at the mid‐points of their central C—C bonds. These bridging groups link the ZnII centres into a one‐dimensional tape structure that propagates along the crystallographic b direction. The tapes are interlinked into a two‐dimensional layer in the ab plane through N—H...O hydrogen bonds between the monodentate ligands. In addition, the thermal stability and solid‐state photoluminescence properties of the title compound are reported. 相似文献
17.
1,1‐Dibromo‐2,2‐bis(trimethylsilylethynyl)ethene ( 2 ) reacts with two equivalents of 1‐boraadamantane ( 1 ) by 1,1‐organoboration of both trimethylsilylethynyl groups to give a triene 3 bearing two 4‐methylene‐3‐borahomoadamantane moieties in terminal positions. The triene was characterized by one‐ and two‐dimensional 1H, 11B, 13C and 29Si NMR spectroscopy in solution and X‐ray structural analysis in the solid state. The planes of the C double bond are strongly twisted against each other as a result of the bulky substituents, and the surroundings of the boron atoms deviate from the ideal trigonal planar geometry owing to the tension in the tricyclic frameworks. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
18.
Lukas J. Hilpert Bernhard Breit 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(29):10044-10048
A rare case of a parallel kinetic resolution of racemic 1,3‐disubstituted allenes by means of a rhodium‐catalyzed addition to 1,3‐diketones furnishing enantiopure allylic 1,3‐diketones is described. Mechanistic experiments demonstrate that the different allene enantiomers react in parallel to either the diastereomeric E‐ or Z‐allylic 1,3‐diketones with the same absolute configuration of the newly formed stereogenic center. A broad substrate scope demonstrates the synthetic utility of this new method. 相似文献
19.
Reactions of 4,5‐Dihydro‐1,4‐Benzothiazepin‐3(2H)‐one 1,1‐Dioxide and 1,5‐Dihydro‐4,1‐Benzothiazepin‐2(3H)‐one 4,4‐Dioxide Derivatives with Vilsmeier Reagent and DMFDMA 下载免费PDF全文
Taras M. Tarasiuk Tatyana A. Volovnenko Kirill S. Popov Volodymyr V. Medviediev Oleg V. Shishkin Yulian M. Volovenko 《Journal of heterocyclic chemistry》2014,51(3):755-759
The regioselectivity of the interaction between isomeric 4,5‐dihydro‐1,4‐benzothiazepin‐3(2H)‐one 1,1‐dioxide and 1,5‐dihydro‐4,1‐benzothiazepin‐2(3H)‐one 4,4‐dioxide derivatives with the Vilsmeier reagent and DMFDMA (N,N‐dimethylformamide dimethylacetal) has been investigated. The structures of synthesized compounds are confirmed by 1H, 13C NMR, elemental analysis, and X‐ray data. 相似文献
20.
Huan Li Zhikun Zhang Xianghang Shangguan Shan Huang Jun Chen Yan Zhang Jianbo Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(44):12115-12119
Palladium‐catalyzed cross‐coupling reactions of 1,1‐diboronates with vinyl bromides and dibromoalkenes were found to afford 1,4‐dienes and allenes, respectively. These reactions utilize the high reactivities of both 1,1‐diboronates and allylboron intermediates generated in the initial coupling. 相似文献