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1.
Z‐Selective Hydrothiolation of Racemic 1,3‐Disubstituted Allenes: An Atom‐Economic Rhodium‐Catalyzed Dynamic Kinetic Resolution
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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
2.
Unlocking the N2 Selectivity of Benzotriazoles: Regiodivergent and Highly Selective Coupling of Benzotriazoles with Allenes
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Kun Xu Niels Thieme Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2014,53(28):7268-7271
The rhodium‐catalyzed, highly N2‐ and N1‐selective coupling of benzotriazoles with allenes is reported. The exceptionally high N2 and N1 selectivities were achieved by using a rhodium(I)/DPEphos and rhodium(I)/JoSPOphos catalyst, respectively. This method permits the atom‐economic synthesis of valuable branched N2‐ and N1‐allylated benzotriazole derivatives and allows for preliminary studies of their reactivity. 相似文献
3.
Dr. Christoph Schotes Dr. Dmytro Ostrovskyi Johanna Senger Karin Schmidtkunz Prof. Dr. Manfred Jung Prof. Dr. Bernhard Breit 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2164-2168
Homolargazole derivatives, in which the macrocycle of natural largazole is extended by one methylene group, were prepared by the recently developed rhodium‐catalyzed hydrocarboxylation reaction onto allenes. This strategy gives access to both the (18S)‐ and (18R)‐stereoisomers in high stereoselectivity under ligand control. 相似文献
4.
《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
5.
Jun Zheng Bernhard Breit 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3430-3435
A rhodium/photoredox dual catalyzed regiodivergent α‐allylation of amines is described. As an atom‐economic and efficient method, alkynes and allenes are used as allylic electrophile surrogates in this novel protocol. With different reaction conditions, synthetically useful branched or linear homoallylic amines could be synthesized in good to excellent yields and regioselectivity. This straightforward strategy complements the traditional transition‐metal catalyzed allylation reactions. 相似文献
6.
Atom‐Economical Dimerization Strategy by the Rhodium‐Catalyzed Addition of Carboxylic Acids to Allenes: Protecting‐Group‐Free Synthesis of Clavosolide A and Late‐Stage Modification
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Alexander M. Haydl Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2015,54(51):15530-15534
Natural products of polyketide origin with a high level of symmetry, in particular C2‐symmetric diolides as a special macrolactone‐based product class, often possess a broad spectrum of biological activity. An efficient route to this important structural motif was developed as part of a concise and highly convergent synthesis of clavosolide A. This strategy features an atom‐economic “head‐to‐tail” dimerization by the stereoselective rhodium‐catalyzed addition of carboxylic acids to terminal allenes with the simultaneous construction of two new stereocenters. The excellent efficiency and selectivity with which the C2‐symmetric core structures were obtained are remarkable considering the outcome under classical dimerization conditions. Furthermore, this approach facilitates late‐stage modification and provides ready access to potential new lead structures. 相似文献
7.
Regio‐ and Enantioselective Synthesis of N‐Substituted Pyrazoles by Rhodium‐Catalyzed Asymmetric Addition to Allenes
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Alexander M. Haydl Dr. Kun Xu Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2015,54(24):7149-7153
The rhodium‐catalyzed asymmetric N‐selective coupling of pyrazole derivatives with terminal allenes gives access to enantioenriched secondary and tertiary allylic pyrazoles, which can be employed for the synthesis of medicinally important targets. The reaction tolerates a large variety of functional groups and labelling experiments gave insights into the reaction mechanism. This new methodology was further applied in a highly efficient synthesis of JAK 1/2 inhibitor (R)‐ruxolitinib. 相似文献
8.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(6):1542-1546
The rhodium‐catalyzed atom‐economic asymmetric N‐selective intermolecular addition of purine derivatives to terminal allenes is reported. Branched allylic purines were obtained in high yields, regioselectivity and outstanding enantioselectivity utilizing a Rh/Josiphos catalyst. Conversely, linear selective allylation of purines could be realized in good to excellent regio‐ and E/Z‐selectivity with a Pd/dppf catalyst system. Furthermore, the new methodology was applied to a straightforward asymmetric synthesis of carbocyclic nucleoside abacavir. 相似文献
9.
Rhodium‐Catalyzed Chemo‐, Regio‐, and Enantioselective Addition of 2‐Pyridones to Terminal Allenes
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Dr. Changkun Li Matthias Kähny Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2014,53(50):13780-13784
A rhodium‐catalyzed chemo‐, regio‐, and enantioselective addition of 2‐pyridones to terminal allenes to give branched N‐allyl 2‐pyridones is reported. Preliminary mechanistic studies support the hypothesis that the reaction was initiated from the more acidic 2‐hydroxypyridine form, and the initial kinetic O‐allylation product was finally converted into the thermodynamically more stable N‐allyl 2‐pyridones. 相似文献
10.
Rhodium‐Catalyzed Arylation of Cyclopropenes Based on Asymmetric Direct Functionalization of Three‐Membered Carbocycles
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Dr. Longyang Dian Prof. Dr. Ilan Marek 《Angewandte Chemie (International ed. in English)》2018,57(14):3682-3686
A variety of highly diastereo‐ and enantiomerically enriched arylcyclopropanes is obtained through the asymmetric rhodium‐catalyzed arylation reaction of achiral nonfunctionalized cyclopropene derivatives with commercially available aryl boronic acids in the presence of (R,S)‐Josiphos. 相似文献
11.
Reactivity of mixed organozinc and mixed organocopper reagents: 11. Nickel‐catalyzed atom‐economic aryl–allyl coupling of mixed (n‐alkyl)(aryl)zincs
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Melike Kalkan 《应用有机金属化学》2014,28(9):725-732
Group selectivity in the allylation of mixed (n‐butyl)(phenyl)zinc reagent can be controlled by changing reaction parameters. CuCN‐catalyzed allylation in tetrahydrofuran (THF)–hexamethylphosphoric triamide is n‐butyl selective and also γ‐selective in the presence of MgCl2, whereas CuI‐catalyzed allylation in THF in the presence of n‐Bu3P takes place with a n‐butyl transfer:phenyl transfer ratio of 23:77 and an α:γ transfer ratio of phenyl of 76:24. NiCl2(Ph3P)2‐catalyzed allylation in the presence of LiCl is phenyl selective with an α:γ ratio of 65:35. The reaction of methyl‐ or n‐butyl(aryl)zinc reagents with an allylic electrophile in THF at room temperature in the presence of NiCl2(Ph3P)2 catalyst and LiCl as an additive provides an atom‐economic alternative to aryl–allyl coupling using diarylzincs. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
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
13.
Rhodium‐Catalyzed Hydroformylation of 1,1‐Disubstituted Allenes Employing the Self‐Assembling 6‐DPPon System
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Alexander Köpfer Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2015,54(23):6913-6917
A rhodium‐catalyzed hydroformylation of 1,1‐disubstituted allenes is reported. Using a RhI/6‐DPPon catalyst system, one can obtain β,γ‐unsaturated aldehydes in high regio‐ and chemoselectivity. The Z‐configured product is formed with up to >95 % selectivity when unsymmetrically 1,1‐disubstituted allenes are submitted to the reaction conditions. This is the first time that these interesting building blocks are accessible by hydroformylation of allenes. The utility of this methodology is demonstrated by further transformations of one of the obtained products. 相似文献
14.
Dr. Sílvia Osuna Dr. Alpay Dermenci Prof. Scott J. Miller Prof. K. N. Houk 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(42):14245-14253
The stereoselective Rauhut–Currier (RC) reaction catalyzed by a cysteine derivative has been explored computationally with density functional theory (M06‐2X). Both methanethiol and a chiral cysteine derivative were studied as nucleophiles. The complete reaction pathway involves rate‐determining elimination of the thiol catalyst from the Michael addition product. The stereoselective Rauhut–Currier reaction, catalyzed by a cysteine derivative as a nucleophile, has also been studied in detail. This reaction was experimentally found to be extremely sensitive to the reaction conditions, such as the number of water equivalents and the effect of potassium counterion. The E1cB process for catalyst elimination has been explored computationally for the eight possible stereoisomers. The effect of explicit water solvation and the presence of counterion (either K+ or Na+) has been studied for the lowest energy enantiomer pair (1S, 2R, 3S)/(1R, 2S, 3R). 相似文献
15.
Atom‐Economic,Regiodivergent, and Stereoselective Coupling of Imidazole Derivatives with Terminal Allenes
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Kun Xu Niels Thieme Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2014,53(8):2162-2165
New Rh‐ and Pd‐catalyzed regiodivergent and stereoselective intermolecular coupling reactions of imidazole derivatives with mono‐substituted allenes are herein reported. Using a RhI/Josiphos system, perfect regioselectivities and high enantiomeric excess were obtained, while a PdII/dppf system gave linear products with high regioselectivities and high E/Z selectivities. This method permits the atom economic synthesis of valuable branched and linear allylic imidazole derivatives. 相似文献
16.
Jzsef Deli Erzsbet
sz Júlia Visy Ferenc Zsila Mikls Simonyi Gyula Tth 《Helvetica chimica acta》2001,84(1):263-270
The (3R,5′R,6′R)‐ and (3R,5′R,6′S)‐capsanthol‐3′‐one (=3,6′‐dihydroxy‐β,κ‐caroten‐3′‐one; 4 and 5 , resp.) were reduced by different complex metal hydrides containing organic ligands. The ratio of the thus obtained diastereoisomeric (3′S)‐capsanthols 2 and 3 or (3′R)‐capsanthols 6 and 7 , respectively, was investigated. Four complex hydrides showed remarkable stereoselectivity and produced the (3′R,6′S)‐capsanthol ( 6 ) in 80 – 100% (see Table 1). The starting materials and the products were characterized by UV/VIS, CD, 1H‐ and 13C‐NMR, and mass spectra. 相似文献
17.
Starting from simple aromatic aldehydes and acetylfuran, (E)‐1‐(furan‐2‐yl)‐3‐arylprop‐2‐en‐1‐ones ( 2 ) were synthesized in high yields. Cyclopropanation of the C?C bond with trimethylsulfoxonium iodide (Me3SO+I?) furnished (furan‐2‐yl)(2‐arylcyclopropyl)methanones 3 in 90–97% yields. Selective conversion of cyclopropyl ketones to their (E)‐ and (Z)‐oxime ethers 5 and oxazaborolidine‐catalyzed stereoselective reduction of the C?N bond followed by separation of the formed diastereoisomers, furnished (2‐arylcyclopropyl)(furan‐2‐yl)methanamines 6 in optically pure form and high yield. Oxidation of the furan ring of (S,S,S)‐, (S,R,R)‐, (R,S,S)‐, and (R,R,R)‐ 6a afforded the four stereoisomers of α‐(2‐phenylcyclopropyl) glycine ( 1a ). 相似文献
18.
Hiromitsu Sogawa Masashi Shiotsuki Fumio Sanda 《Journal of polymer science. Part A, Polymer chemistry》2012,50(10):2008-2018
Novel optically active substituted acetylenes HC? CCH2CR1(CO2CH3)NHR2 [(S)‐/(R)‐ 1 : R1 = H, R2 = Boc, (S)‐ 2 : R1 = CH3, R2 = Boc, (S)‐ 3 : R1 = H, R2 = Fmoc, (S)‐ 4 : R1 = CH3, R2 = Fmoc (Boc = tert‐butoxycarbonyl, Fmoc = 9‐fluorenylmethoxycarbonyl)] were synthesized from α‐propargylglycine and α‐propargylalanine, and polymerized with a rhodium catalyst to provide the polymers with number‐average molecular weights of 2400–38,900 in good yields. Polarimetric, circular dichroism (CD), and UV–vis spectroscopic analyses indicated that poly[(S)‐ 1 ], poly[(R)‐ 1 ], and poly[(S)‐ 4 ] formed predominantly one‐handed helical structures both in polar and nonpolar solvents. Poly[(S)‐ 1a ] carrying unprotected carboxy groups was obtained by alkaline hydrolysis of poly[(S)‐ 1 ], and poly[(S)‐ 4b ] carrying unprotected amino groups was obtained by removal of Fmoc groups of poly[(S)‐ 4 ] using piperidine. Poly[(S)‐ 1a ] and poly[(S)‐ 4b ] also exhibited clear CD signals, which were different from those of the precursors, poly[(S)‐ 1 ] and poly[(S)‐ 4 ]. The solution‐state IR measurement revealed the presence of intramolecular hydrogen bonding between the carbamate groups of poly[(S)‐ 1 ] and poly[(S)‐ 1a ]. The plus CD signal of poly[(S)‐ 1a ] turned into minus one on addition of alkali hydroxides and tetrabutylammonium fluoride, accompanying the red‐shift of λmax. The degree of λmax shift became large as the size of cation of the additive. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
19.
Kun Xu Niels Thieme Bernhard Breit 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(8):2194-2197
New Rh‐ and Pd‐catalyzed regiodivergent and stereoselective intermolecular coupling reactions of imidazole derivatives with mono‐substituted allenes are herein reported. Using a RhI/Josiphos system, perfect regioselectivities and high enantiomeric excess were obtained, while a PdII/dppf system gave linear products with high regioselectivities and high E/Z selectivities. This method permits the atom economic synthesis of valuable branched and linear allylic imidazole derivatives. 相似文献
20.
Lukas J. Hilpert Simon V. Sieger Alexander M. Haydl Bernhard Breit 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3416-3419
A complementing Pd‐ and Rh‐catalyzed dynamic kinetic resolution (DKR) of racemic allenes leading to N‐allylated pyrazoles is described. Such compounds are of enormous interest in medicinal chemistry as certified drugs and potential drug candidates. The new methods feature high chemo‐, regio‐ and enantioselectivities aside from displaying a broad substrate scope and functional group compatibility. A mechanistic rational accounting for allene racemization and trans‐alkene selectivity is discussed. 相似文献