Unexpected side reaction is discovered from the N-H insertion of phenyl diazoacetates with arylamines in the presence of Rh2(OAc)4 catalyst. This side reaction is not evident with copper catalysts such as Cu(acac)2 or...Unexpected side reaction is discovered from the N-H insertion of phenyl diazoacetates with arylamines in the presence of Rh2(OAc)4 catalyst. This side reaction is not evident with copper catalysts such as Cu(acac)2 or Cu(OTf)2. Good yield of the N-H insertion was obtained by using 0.2% of copper catalyst.展开更多
1,10-Phenanthrolinium N-ylides,can react with malonitrile and aromatic aldehydes via a domino-Knoevenagel cyclization to afford a new class of trihydropyrrolo[1,2-a][l,10]phenanthroline derivatives as stable helical c...1,10-Phenanthrolinium N-ylides,can react with malonitrile and aromatic aldehydes via a domino-Knoevenagel cyclization to afford a new class of trihydropyrrolo[1,2-a][l,10]phenanthroline derivatives as stable helical compounds in a simple,mild,and efficient protocol in excellent yields.展开更多
The base mediated cycloaddition reactions of 4-dimethylamino-l-phenacylpyridinium bromides with two mo- lecular 3-phenaeylideneoxindoles in methylene dichloride afforded functionalized dispirocyclopentyl-3,3＇-bisoxin...The base mediated cycloaddition reactions of 4-dimethylamino-l-phenacylpyridinium bromides with two mo- lecular 3-phenaeylideneoxindoles in methylene dichloride afforded functionalized dispirocyclopentyl-3,3＇-bisoxin- doles in good yields and with high diastereoselectivity. The similar cycloaddition reactions of 1-（N,N-dialkylcarba- moylmethyl） and 1-cyanomethyl 4-dimethylamino-pyridinium bromide in refluxing ethanol in the presence of triethylamine a/so resulted in dispirocyclopentyl-3,3＇-bisoxindoles with high diastereoselectivity. The stereochemis- try of dispirocyclopentyl-3,3＇-bisoxindoles was elucidated on the basis of ^1H NMR data and single crystal struc- tures.展开更多
A synergistic rhodium（Ⅱ）/phosphoric acid catalyzed three component reaction of 3-diazooxindoles,alcohols and N-benzhydryl-α-imino ester is developed for the efficient construction of chiral β-alkoxy C-β-tetrasub...A synergistic rhodium（Ⅱ）/phosphoric acid catalyzed three component reaction of 3-diazooxindoles,alcohols and N-benzhydryl-α-imino ester is developed for the efficient construction of chiral β-alkoxy C-β-tetrasubstituted α-amino acid derivatives in good yields and with excellent diastereoselectivities and high enantioselectivities.The synthetic application of the resulting products was illustrated by reducing with Pd/C under H_2 atmosphere followed reacting with CSCl_2 at room temperature to rapid afford 3-spirocyclic oxindole in a good yield with a chirality retainment.The three-component reaction is proposed to proceed through an electrophilic trapping of the oxonium ylides by N-benzhydryl-α-imino ester.展开更多
基金We are grateful for financial support from the Chinese Academy of Sciences and National Nature Science Foundation of China(20202011).
文摘Unexpected side reaction is discovered from the N-H insertion of phenyl diazoacetates with arylamines in the presence of Rh2(OAc)4 catalyst. This side reaction is not evident with copper catalysts such as Cu(acac)2 or Cu(OTf)2. Good yield of the N-H insertion was obtained by using 0.2% of copper catalyst.
基金financial support from the Research Council of University of Sistan and Balouchestan
文摘1,10-Phenanthrolinium N-ylides,can react with malonitrile and aromatic aldehydes via a domino-Knoevenagel cyclization to afford a new class of trihydropyrrolo[1,2-a][l,10]phenanthroline derivatives as stable helical compounds in a simple,mild,and efficient protocol in excellent yields.
文摘The base mediated cycloaddition reactions of 4-dimethylamino-l-phenacylpyridinium bromides with two mo- lecular 3-phenaeylideneoxindoles in methylene dichloride afforded functionalized dispirocyclopentyl-3,3＇-bisoxin- doles in good yields and with high diastereoselectivity. The similar cycloaddition reactions of 1-（N,N-dialkylcarba- moylmethyl） and 1-cyanomethyl 4-dimethylamino-pyridinium bromide in refluxing ethanol in the presence of triethylamine a/so resulted in dispirocyclopentyl-3,3＇-bisoxindoles with high diastereoselectivity. The stereochemis- try of dispirocyclopentyl-3,3＇-bisoxindoles was elucidated on the basis of ^1H NMR data and single crystal struc- tures.
基金NSFC (No. 21332003)STCSM (No. 15ZR1411000)Stake Key Laboratory of Advanced Technology for Materials Synthesis and Processing (2015-KF-11) for financial support
文摘A synergistic rhodium（Ⅱ）/phosphoric acid catalyzed three component reaction of 3-diazooxindoles,alcohols and N-benzhydryl-α-imino ester is developed for the efficient construction of chiral β-alkoxy C-β-tetrasubstituted α-amino acid derivatives in good yields and with excellent diastereoselectivities and high enantioselectivities.The synthetic application of the resulting products was illustrated by reducing with Pd/C under H_2 atmosphere followed reacting with CSCl_2 at room temperature to rapid afford 3-spirocyclic oxindole in a good yield with a chirality retainment.The three-component reaction is proposed to proceed through an electrophilic trapping of the oxonium ylides by N-benzhydryl-α-imino ester.
