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1.
An efficient synthesis of enantiomerically pure aromatic-fused N-containing heterocycles was successfully achieved via Pd-catalyzed intramolecular C-N bond formation between the nitrogen originated from the aziridine and the halogen containing aromatic carbon. This reaction has a broad substrate scope to provide various enantiomerically pure (3,4-dihydro-2H-benzo[b][1,4]oxazin-3-yl)methanols, 2-hydroxymethyl-1,2,3,4-tetrahydroquinolines and (1,2,3,4-tetrahydroquinoxalin-2-yl)methanols from common chiral aziridines in good yields. 相似文献
2.
Alejandro Cruz Itzia I. Padilla-MartínezEfrén V. García-Báez 《Tetrahedron: Asymmetry》2011,22(4):394-398
The reaction of chlorodeoxypseudoephedrine or chlorodeoxynorpseudoephedrine hydrochlorides with sodium dithiocarbonate in stirring ethanol at 0 °C to stereoselectively afford the corresponding cis-thiazolidinethiones in good yields (81% and 95%) is reported. The in situ formation of a cis-aziridine to explain the presence of trans-thiazolidinethione as a side product is proposed when the same reaction was carried out at room temperature. In addition, a 70:30 mixture of trans-isomers of a thiazolidinethione/isothiazolidinethione was formed when a cis-aziridine NH was reacted with carbon disulfide in refluxing ethanol. The analogous reaction with cis-aziridine N-Me stereoselectively affords the corresponding cis-thiazolidinethione. The 1H and 13C NMR data of the thiazolidinethiones were assigned. cis-3,4-Dimethyl-5-phenylthiazolidine-2-thione was crystallized from ethanol and its X-ray diffraction structure was analyzed. 相似文献
3.
A range of substituted alkynyl aziridines undergo a ring expansion to afford 2,5-substituted pyrroles under gold catalysis. While effective conditions can be generated from other gold sources, a combination of Ph3PAuCl and AgOTs generate a catalyst system that provides extremely clean cycloisomerisation reactions requiring minimal work-up and purification. 相似文献
4.
Morton D Pearson D Field RA Stockman RA 《Chemical communications (Cambridge, England)》2006,(17):1833-1835
The direct preparation of a range of variously substituted chiral tert-butylsulfinylketimines was achieved in good yield (41-90%), with relatively rapid reaction times (4-15 hours); their synthetic application was examined through the reaction with the ylides derived from trimethylsulfonium iodide and S-allyl tetrahydrothiophenium bromide, affording convenient access to a diverse range of highly substituted chiral aziridines in up to 78% yield and > 90% d.e. 相似文献
5.
An efficient and general synthesis of aziridines by the reaction of imines derived from p-toluenesulfonamides with in situ generated iodomethyllithium, with a simple and rapid experimental protocol, is reported for the first time. The reaction with the chiral aldimine derived from phenylalaninal allowed access to (2R,1'S)-2-(1'-aminoalkyl)aziridine with very high diastereoselectivity, in enantiopure form. A mechanism to explain this novel reaction is proposed. 相似文献
6.
A new synthesis of enamides from ketones is disclosed that involves a phosphine-mediated reductive acylation of oximes. The resulting enamides are isolated in good yields (up to 89%) and excellent purity, permitting a subsequent hydrogenation to access enantiopure acetamides at catalyst loadings practical for large-scale applications. 相似文献
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A general and facile synthesis of enantiopure 1-deoxyazasugars was achieved from stereoselective dihydroxylation of a common synthetic intermediate, piperidine ring fused oxazolidin-2-one, originating from a commercially available starting substrate, chiral aziridine-2-carboxylate, in high yields. 相似文献
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Jung Ho Lee 《Tetrahedron letters》2007,48(16):2889-2892
An efficient, practical and enantioselective total synthesis of (+)-decursinol, which has diverse range of biological properties including anti-cancer, anti-Helicobacter pylori, and strong antinociceptive activities, has been achieved in five steps with 41.4% overall yield from umbelliferone. The improved ring construction from coumarin to linear pyranocoumarin has been obtained through quinonemethide intermediate by using phenylboronic acid with propionic acid. 相似文献
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Ahmed Kamal Moku Balakrishna Papagari Venkat Reddy Shaikh Faazil 《Tetrahedron: Asymmetry》2010,21(20):2517-2523
An efficient synthesis of synargentolide A is described by using d-mannitol and d-malic acid. The key features of the synthetic strategy include Wittig olefination, ring closing-metathesis reaction and cross-metathesis reaction for the formation of synargentolide A. 相似文献
14.
Two synthetic routes to isocarbacyclin starting from furfural are described. One route involves the regioselective hydrogenation of the disubstituted olefin in the presence of two other olefinic double bonds, and the other includes the highly regioselective organocopper coupling with the allylic etectrophile as a key step. 相似文献
15.
[reaction: see text] Pyrimidinones 3 were chemoselectively reduced by using metal-catalyzed hydrogenation and stereoselectively substituted by various nucleophiles. Starting from beta-amino alcohols 1, the overall process allows efficient access to substituted pyrimidines 4 and 6. 相似文献
16.
In the presence of tBuOK, reaction of acetylenes with N-Ts substituted aziridines derived from both cyclic and acyclic alkenes at room temperature gave rise to homopropargylamines in good to high yields and in high regioselectivity. Not only Ph- and Me3Si-substituted acetylenes but also acetylene itself was suitable reagents. Treatment of ring-opening products with I2 and AgOAc in the presence of K2CO3 provided dihydropyrroles in high yields. One-pot synthesis of dihydropyrroles was also realized by the reaction of aziridines and phenylacetylene in the presence of NaH followed by the treatment with I2 and AgOAc. 相似文献
17.
Park CS Kim MS Sim TB Pyun DK Lee CH Choi D Lee WK Chang JW Ha HJ 《The Journal of organic chemistry》2003,68(1):43-49
Enantiomerically pure N-(R)-alpha-methylbenzyl-4(R)-(chloromethyl)oxazolidinones (4R)-5a-k were synthesized in one step and high yields from various aziridine-2-methanols (S)-2a-k by intramolecular cyclization with phosgene. The alpha-methylbenzyl substituent on the nitrogen was easily cleaved to give both enanatiomers of 4-(chloromethyl)oxazolidinones (R)-7a and (S)-7a. (R)-7a was used for the efficient syntheses of (L)-homophenylalaninol analogues (S)-12a-j. We also applied the same methodology to prepare oxazolidinones 9a-c containing a heteroatom-substituted alkyl group at C-4 in high yields. 相似文献
18.
In the presence of phosphite or phosphine, the reaction between 4-, 2-nitrobenzaldehyde and methylidenemalononitriles proceeded smoothly to give the cyclopropane derivatives in high yields, while the reaction between 4-, 2-benzaldehyde, and N-tosylbenzaldimines afforded the azidridine derivatives in moderate to high yields. A plausible mechanism was proposed and the strongly electron-withdrawing nitro-group is believed to play a critical role in these transformations. 相似文献
19.
Akundi Surya Prabhakar 《Tetrahedron letters》2007,48(49):8709-8711
An efficient one-pot synthesis of vinylogous carbamates is reported starting from alkyl azides by using NH4Cl/Zn dust. 相似文献
20.
Treatment of aliphatic, aromatic as well as heterocyclic acid chlorides with sulfonamide in sulfolane at 120°C for 3 hours produces the corresponding nitriles in high yields. 相似文献