A facile synthesis of chromeno[4,3-b]pyrroles derived from allyl derivatives of Baylis-Hillman adducts through intramolecular 1,3-dipolar cycloaddition using ultrasonication

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.     

Baylis-Hillman反应机理研究进展

介绍了一种形成碳—碳键的方法——Baylis-Hillman反应, 综述了单分子醛、双分子醛反应机理、TiCl₄催化机理、不对称诱导机理以及低温效应、溶剂效应、离子液体反应机理的研究进展.     

Silicon- and germanium-substituted propynals as ambident electrophiles for the design of new heterocycles and polyfunctional acetylenes

Research results on the reactivity of silicon- and germanium-substituted propynals as ambident electrophiles in the reactions with mono- and binucleophiles were summarized. Chemo- and regioselectivity of the nucleophilic addition and cycloaddition depending on the structure of propynals, the nature of a reagent, catalyst, and the reaction conditions was studied. Wide synthetic potentialities of substituted propynals in the synthesis of new heterocyclic systems and polyfunctional acetylenes were demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 914–930, May, 2008.     

The total synthesis of eupomatilones 2 and 5

Efficient and diastereocontrolled syntheses of natural lignans eupomatilone 2 (1) and 5 (2) are described. Biaryl coupling was achieved using Suzuki chemistry. The lactone moiety was constructed using allylmetal reagents, which were synthesized from Baylis-Hillman adducts. Allylindium reagents were found to be most effective.     

Baylis-Hillman reaction promoted by a recyclable protic-ionic-liquid solvent-catalyst system: DABCO-AcOH-H2O

A recyclable protic-ionic-liquid solvent-catalyst system, DABCO-AcOH-H₂O, has been developed and used in the Baylis-Hillman reaction of aromatic aldehydes, aliphatic aldehydes, and cinnamaldehydes with acrylates and acrylonitrile, showing comparable performance to free DABCO in traditional solvents. The DABCO-AcOH-H₂O solvent-catalyst system could be reused for at least five times without significant loss of activity.     

Simple, facile and one-pot conversion of the Baylis-Hillman acetates into 3,5,6-trisubstituted-2-pyridones

A facile route for the synthesis of novel 3,5,6-trisubstituted-2-pyridones from the acetylated Baylis-Hillman esters with β-enamino esters or β-enamino nitriles in one pot with good yields is described.     

TfOH-catalyzed allylation of alkynes with cyclic Baylis-Hillman alcohols

The substitution reaction of cyclic Baylis-Hillman alcohols with arylacetylenes was achieved under the catalysis of TfOH in nitromethane. The γ,δ-unsaturated ketones were obtained in moderate to good yields.     

Expedient synthesis of highly substituted α-pyrones from Baylis-Hillman adducts and their conversion to poly-substituted aromatics

An efficient synthetic protocol of fully substituted α-pyrones has been developed starting from the Baylis-Hillman adducts. Subsequent Diels-Alder reaction of the α-pyrones and DMAD produced poly-substituted aromatic compounds in high yields.     

Lewis acid- and/or Lewis base-catalyzed [3+2] cycloaddition reaction: synthesis of pyrazoles and pyrazolines

A facile, InCl₃ and/or DABCO mediated 1, 3-dipolar cycloaddition of ethyl diazoacetate (EDA) with various activated olefins under solvent-free conditions at ambient temperature to afford 3, 5-disubstituted pyrazolines and pyrazoles in moderate to good yields is reported.