Facile domino reactions for the stereoselective assembly of highly functionalized bis-(trans-2,3-dihydrofuranyl) sulfides
作者:Beer Mohamed Vinosha、Subbu Perumal、Subbiah Renuga、Abdulrahman I. Almansour
DOI:10.1016/j.tetlet.2013.03.088
日期:2013.5
facile stereoselective synthesis of a series of nineteen novel bis-(trans-2,3-dihydrofuranyl) sulfides from the reaction of (Z,Z)-2,2′-thiobis(1,3-diarylprop-2-en-1-ones) with substituted phenacyl bromides and pyridine in the presence of K2CO3 in acetonitrile via domino reactions is described. This transformation presumably occurs via pyridinium salt formation/ylide generation/Michael addition/intramolecular
从(Z,Z)-2,2'-硫代双(1,3-二芳基丙-2-烯-1)反应中轻松合成一系列十九种新型双-(反--2,3-二氢呋喃基)硫化物描述了在乙腈中通过多米诺反应在K 2 CO 3存在下用取代的苯甲酰基溴和吡啶制得的α-酮。这种转化大概是通过吡啶鎓盐的形成/内鎓盐的生成/迈克尔加成/分子内的多米诺骨牌序列发生的,涉及在单个步骤中形成两个C-C和两个C-O键和四个立体中心,而完全的立体选择性仅提供一个非对映异构体。
Novel Domino Reactions of (<i>Z</i>,<i>Z</i>)-2,2′-Thiobis(1,3-diarylprop-2-en-1-ones) with Acetylacetone and Ethyl Acetoacetate: Stereoselective Synthesis of Highly Functionalized Dihydrofurans
Abstract The domino reactions of (Z,Z)-2,2′-thiobis(1,3-diarylprop-2-en-1-ones) with acetylacetone and ethylacetoacetate in the presence of sodium ethoxide afforded the corresponding 4,5-dihydrofurans stereoselectively in moderate yields presumably via a Michael addition–enolization–displacement sequence.
Stereoselective Synthesis of Polyfunctionalized Nitrothianes: Enhancement of Stereoselectivity by Microwaves
作者:Beermohamed Vinosha、Subbiah Renuga、Subbu Perumal、Packianathan Thomas Muthiah、Kaliyaperumal Thanigaimani
DOI:10.1080/00397911.2012.683970
日期:2013.7.18
The Michael addition of nitromethane to (Z,Z)-2,2-thiobis(1,3-diarylprop-2-en-1-ones) in the presence of NaOEt in dimethylformamide (DMF)/alcohol under thermal conditions affords a diastereomeric mixture of 2a,6e-diaroyl-3a,5e-diaryl-4e-nitrothianes and 2e,6e-diaroyl-3e,5e-diaryl-4e-nitrothianes with a dr of approximate to 3:1/4:1 respectively. This reaction under microwave irradiation in DMF/alcohol afforded solely 2a,6e-diaroyl-3a,5e-diaryl-4e-nitrothianes, disclosing enhancement of stereoselectivity by microwaves. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) to view the free supplemental file.
A novel four-component tandem protocol for the stereoselective synthesis of highly functionalised thiazoles
aromatic aldehydes and ammonium acetate in 1:2:1 molar ratio under solvent-free microwave irradiation afforded predominantly a series of thiazoles, viz., 1-aryl-2-[5(Z)-5-arylmethylidene-2,4-diaryl-2,5-dihydrothiazol-2-yl]ethanones stereoselectively. This reaction presumably occurs via a Knoevenagel condensation–Michael addition–cyclocondensation–ring opening–ring closing Michael addition sequence