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211.
Sung Hwan Kim 《Tetrahedron letters》2009,50(15):1696-3242
We developed an efficient synthetic method of diallylated δ-valerolactam and γ-butyrolactam derivatives via an indium-mediated successive double Barbier type allylations starting from the Baylis-Hillman adducts. 相似文献
212.
Through the use of [PdCl(C3H5)]2/cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides undergoes Heck reaction using 2- or 3-subtituted allylic alcohols. With these sterically congested alkenes, the selective formation of β-aryl ketones was observed when appropriate reaction conditions were used. The influence of the functional group on the aryl bromide and of the base on the selectivity is remarkable. With several substrates, much higher selectivities were obtained using NaHCO3 instead of K2CO3 as base. Furthermore, this catalyst can be used at low loading with several substrates. 相似文献
213.
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
214.
The synthesis of substituted 3-methylene-2-pyridones via SN2 displacement reaction of nucleophiles bearing a keto group on the acetyl derivative of Baylis-Hillman adducts of acrylonitrile followed by TFA/H2SO4-mediated intramolecular cyclization is described. The utility of these pyridone derivatives for the synthesis of new spiroisoxazolines in highly regio- and stereo-selective fashion is also illustrated. The structure of the spiroisoxazolines has been secured via X-ray crystallographic analysis. 相似文献
215.
The first successful intermolecular Heck reaction between Baylis-Hillman adducts and aryl iodides was achieved under the conditions comprising Pd(OAc)2/n-Bu4NBr/KOAc in CH3CN. 相似文献
216.
An asymmetric nickel-chromium coupling strategy has been employed in the generation of enantioenriched Baylis-Hillman adducts with selectivities reaching >90% ee and in fair to moderate yields (up to 65%) using a chiral sulfonamide ligand. The reaction conditions appear to show reasonable generality and are compatible with both aromatic and aliphatic aldehydes. Utilizing such a strategy not only allows for the preparation of products which contain substitution at the β-position on the olefin but also allows for the separation of olefin isomers in this transformation. 相似文献
217.
2-Formylphenylboronic acids upon reaction with activated olefins such as acrylates, methyl vinyl ketone, and acrylonitrile provide functionalized benzoboroxoles. The corresponding homologated benzoboroxoles were synthesized via the reaction of 2-formylphenylboronic acids with α-bromomethylacrylates. 相似文献
218.
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
219.
Without additional reagents, the Baylis-Hillman acetates 2 underwent nucleophilic substitution reaction with imidazole readily in aqueous THF solution to afford the corresponding N-substituted imidazole derivatives 3 in good to excellent yields. Moreover, the reaction between the in situ generated DABCO salt of Baylis-Hillman acetates 4 and imidazole occurs in aqueous THF providing the SN2 type products 5. The simpler operational procedure, better stereoselectivity and higher efficiency over conventional method make the present protocol practical for the preparation of imidazole derivatives. 相似文献