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1.
Baylis-Hillman bromides have been successfully employed as a valuable source of 1,3-dipoles for cycloaddition onto dialkyl azodicarboxylates (dipolarophiles) under the influence of dimethyl sulfide and potassium carbonate to provide functionalized dihydropyrazole derivatives in a simple one-pot [3+2] annulation strategy. 相似文献
2.
Polysubstituted phenol derivatives were synthesized from the acetates of Baylis-Hillman adducts and dimethyl 1,3-acetonedicarboxylate (DMAD) in a one-pot reaction via the sequential SN2′ reaction, aldol condensation, and 1,3-H shift process. 相似文献
3.
Bhahwal A. Shah Vijay K. Sethi Samar S. Andotra Ghulam N. Qazi 《Tetrahedron letters》2007,48(6):955-960
The Baylis-Hillman reaction of a sesquiterpene lactone parthenin with various aldehydes gave unexpected products containing a 1,3-dioxolane moiety. Both small aliphatic and aromatic aldehydes produced 1,3-dioxolanes, whereas higher aliphatic aldehydes produced normal Baylis-Hillman products. 相似文献
4.
R. Saxena 《Tetrahedron》2004,60(45):10311-10320
Results of the catalytic hydrogenation of Baylis-Hillman adducts obtained from substituted 3-, 4- and 5-isoxazolecarbox-aldehydes and their corresponding acetates in the presence of Raney-Ni and Pd-C are presented. The hydrogenation of Baylis-Hillman adducts of substituted 5-isoxazolecarbaldehydes and 3-isoxazolecarbaldehydes in the presence of Raney-Ni furnishes diastereoselectively syn enaminones over anti and in the presence of boric acid as an additive further enhancement of diastereoselectivity in favor of syn isomer is observed. The Pd-C-promoted hydrogenation of these substrates is also diastereoselective in favor of syn isomer but occurs without the hydrogenolysis of isoxazole-ring. The presence of boric acid as an additive in this hydrogenation exhibits no pronounced effect on diastereoselectivity. The Raney-Ni-mediated hydrogenation of Baylis-Hillman adducts of substituted 4-isoxazolecarbaldehydes yield pyridone derivatives and Pd-C-promoted hydrogenation of the same substrate is diastereoselective to afford the anti isomer of the resulting products. The enaminones derived from Baylis-Hillman adducts of 3- and 5-isoxazolecarbaldehydes serve as versatile precursors for α′-hydroxy-1,3-diketones, which undergo acid-catalyzed ring-closure reaction to afford the furanone derivatives in excellent yields. 相似文献
5.
Jayadevan Jayashankaran 《Tetrahedron letters》2006,47(31):5535-5538
The synthesis of a series of novel spiropyrrolidines and polycyclic heterocycles has been accomplished by 1,3-dipolar cycloaddition reactions with Baylis-Hillman adducts. The reaction also yielded novel furo[3,4-b]pyrrole in some cases by an unusual cyclization. 相似文献
6.
Subban Kathiravan 《Tetrahedron letters》2009,50(45):6116-6120
A one-pot synthesis of ferrocene-grafted dispiropyrrolidine/pyrrolizidine scaffolds has been accomplished in good yields through a facile 1,3-dipolar cycloaddition of various azomethine ylides derived from diketones and secondary amino acids with Baylis-Hillman adduct derived from ferrocene carbaldehyde. The regiochemical and stereochemical outcomes of the cycloaddition reaction were ascertained by X-ray crystallographic studies of one of the cycloadducts. 相似文献
7.
Ekambaram Ramesh 《Tetrahedron letters》2007,48(10):1835-1839
Microwave-assisted synthesis of spiropyrrolidines/pyrrolizidines has been accomplished using the alkene unit of Baylis-Hillman adducts of ninhydrin with sarcosine/proline and various activated ketones through 1,3-dipolar cycloaddition. 相似文献
8.
Synthesis of 4-arylidenecyclohexane-1,3-dione derivatives was carried out from the Baylis-Hillman acetates. The potential utility of the prepared compounds for the synthesis of cyclohexanedione oxime ether herbicides was examined. 相似文献
9.
Alcaide B Almendros P Aragoncillo C Rodríguez-Acebes R 《The Journal of organic chemistry》2004,69(3):826-831
The reaction of various activated vinyl systems, including 2-cyclopenten-1-one, with enantiopure azetidine-2,3-diones 1 was promoted by DABCO to afford the corresponding optically pure Baylis-Hillman adducts 2 without detectable epimerization. However, the reaction of alpha-keto lactams 1 with but-3-yn-2-one was not as successful, giving the corresponding beta-halo Baylis-Hillman adduct in low yield. Metal-mediated bromoallylation reaction between 2,3-dibromopropene and azetidine-2,3-diones 1 was investigated in aqueous media. Surprisingly, indium was unable to promote the bromoallylation reaction of alpha-keto lactams 1, but the Sn-Hf(4)Cl-promoted bromoallylation of ketones 1 proceeded efficiently to achieve bromohomoallyl alcohols 5 as single diastereomers. On this basis, simple and fast protocols for the asymmetric synthesis of the potentially bioactive 3-substituted 3-hydroxy-beta-lactam moiety were developed. 相似文献
10.
An efficient and regioselective introduction method of 2-methylpyridines to the secondary position of Baylis-Hillman adducts has been developed. A base treatment of 2-methylpyridinium salt of Baylis-Hillman bromide generated N-allylenamine intermediate which underwent a facile 3-aza-Cope rearrangement under mild conditions to produce the product. 相似文献
11.
In the Baylis-Hillman reaction of N-benzylidene-4-methyl-benzenesulfonamide with cyclohex-2-en-1-one or cyclopent-2-en-1-one, we found that, in the presence of a catalytic amount of DMAP, the Baylis-Hillman reaction can be greatly accelerated to give the normal Baylis-Hillman adduct 1 or 3 in good or very high yields: moreover, using PBu3 as a Lewis base in the reaction of N-benzylidene-4-methylbenzenesulfonamide with cyclopent-2-en-1-one, the normal Baylis-Hillman adducts 3 could be obtained in very high yields within 5 h, however, using PBu3 or DBU as a Lewis base in the reaction of N-benzylidene-4-methyl-benzenesulfonamide with cyclohex-2-en-1-one, beside the normal Baylis-Hillman adduct 1 abnormal Baylis-Hillman adduct 3-aryl-2-[(4-methylphenyl)sulfonyl]-2-azabicyclo[2.2.2]octan-5-one 2 was formed at the same time; the substituent's effects were also examined. 相似文献
12.
One-pot three component synthesis of novel pyrido[1,4]-oxazepine fused spiropyrrolidines has been accomplished in good yields by 1,3-dipolar cycloaddition reaction of azomethine ylide, derived from paraformaldehyde and sarcosine with (E)-4-benzylidene-hexahydro-1H-pyrido[2,1-c][1,4]-oxazepine-3(7H)-one as dipolarophiles derived from Baylis-Hillman adducts. The effect of solvent on the [3 + 2]-cycloaddition reaction is also studied. 相似文献
13.
The attempted Baylis-Hillman reactions of N-tosyl aldimines and aryl aldehydes with 3-methylpenta-3,4-dien-2-one gave the corresponding Baylis-Hillman adducts 3 and 6 in moderate to good yields in the presence of DMAP in DMSO, respectively. In the case of the aza-Baylis-Hillman reactions of N-tosyl aldimines with 3-methylpenta-3,4-dien-2-one catalyzed by PBu3, the corresponding aza-Baylis-Hillman derivatives 4 and 5 were formed at the same time. 相似文献
14.
The first application of Baylis-Hillman adducts in the synthesis of azetidines is reported. The synthesis involves a one-pot, high yielding and highly diastereoselective annulation of unmodified Baylis-Hillman adducts with N-arylphosphoramidates to afford 1,2-disubstituted azetidine-3-carbonitriles/carboxylates, which are the precursors of biologically versatile azetidine-3-carboxylic acids. 相似文献
15.
Subban Kathiravan 《Tetrahedron letters》2009,50(20):2389-7569
The synthesis of a series of pyrrole-based polycyclic heterocycles has been accomplished through an intramolecular 1,3-dipolar cycloaddition reaction of an azomethine ylide with the dipolarophile derived from Baylis-Hillman adducts. Improved yields of the products were obtained when the reaction was carried out under microwave conditions. 相似文献
16.
A novel regioselective synthesis of a number of functionalized 3-spiropyrrolizidine and 3-spiropyrrolidine oxindoles from Baylis-Hillman adducts of isatin and heteroaldehydes via [3+2] cycloaddition of azomethine ylides in excellent yields has been reported. 相似文献
17.
A facile one-pot synthesis of 3-(2-hydroxyphenyl)indolin-2-ones has been developed via the TiCl4-mediated Baylis-Hillman (B-H) reaction of N-substituted isatins and cyclohex-2-enone, followed by treatment of the in situ generated B-H alcohols with aq HBr. Baylis-Hillman reaction of aromatic cyclic 1,2-diones with cycloalk-2-enones under the influence of TiCl4 has been successfully performed and the resulting Baylis-Hillman adducts have been conveniently transformed into pentacyclic and hexacyclic fused furan derivatives. 相似文献
18.
Ekambaram Ramesh 《Tetrahedron letters》2008,49(7):1125-1128
Synthesis of a series of chromene[4,3-b]pyrroles has been accomplished through an intramolecular 1,3-dipolar cycloaddition reaction of an azomethine ylide with the dipolarophile derived from Baylis-Hillman adducts. Improved yields of the same products were obtained when the reaction was carried out under ultrasonication. 相似文献
19.
Subban Kathiravan 《Tetrahedron letters》2010,51(23):3065-3070
A facile synthesis of a series of naphtho[2,1-b]pyrano pyrrolizidines and indolizidines was accomplished in good yields in a one-pot reaction through intramolecular 1,3-dipolar cycloaddition of azomethine ylides with Baylis-Hillman adducts as dipolarophiles. The protocol is applicable to a wide variety of photochromic and biologically active napthopyrano products. The regio and stereochemical outcome of the cycloaddition reaction was ascertained by X-ray crystallographic study of some of the products. 相似文献
20.
Richa Pathak 《Tetrahedron》2007,63(2):451-460
Trifluoroacetic acid has been discovered to be a highly effective and efficient reagent for the tandem Claisen rearrangement and cyclization reaction to yield 3-arylmethylene-3,4-dihydro-1H-quinolin-2-ones from compounds obtained from the SN2 reaction between anilines and acetyl derivatives of Baylis-Hillman adducts of acrylates in the presence of DABCO. In contrast, similar compounds obtained from the acetyl derivatives of Baylis-Hillman adduct of acrylonitrile on treatment with trifluoroacetic acid directly furnish 3-arylmethyl-2-amino-quinoline via tandem Claisen rearrangement, cyclization and isomerization. 相似文献