Stepwise cycloaddition reaction of N-phenacylbenzothiazolium bromides and nitroalkenes for tetrahydro-, dihydro- and benzo[d] pyrrolo[2,1-b] thiazoles

作者：Jin, Gong; Sun, Jing^*; Yang, Ren-Yin; Yan, Chao-Guo^*

来源：Scientific Reports, 2017, 7(1): 46470.

DOI：10.1038/srep46470

• DIASTEREOSELECTIVE SYNTHESIS
• SUBSTITUTED INDOLIZINES
• PUMMERER REARRANGEMENT
• INTRAMOLECULAR CAPTURE
• DERIVATIVES
• YLIDES
• SALTS
• MALONONITRILE
• SULFONES
• REAGENT

The triethylamine promoted stepwise 1,3-dipolar cycloaddition reaction of N-phenacylbenzothiazolium bromides with nitroalkenes in ethanol resulted in a mixture of two isomeric tetrahydrobenzo[d] pyrrolo[2,1-b] thiazoles with cis/trans/cis- and all-trans-configurations. More importantly, the corresponding dihydrobenzo[d] pyrrolo[2,1-b] thiazoles can be selectively prepared in refluxing ethanol and the benzo[d] pyrrolo[2,1-b] thiazoles can be obtained in satisfactory yields by sequential dehydrogenation with DDQ as oxidizer. On the other hand, the similar cycloaddition reaction of N-phenacylbenzothiazolium bromides with 1-methy-1-nitroalkenes in refluxing ethanol afforded benzo[d] pyrrolo[2,1-b] thiazoles with splitting out of nitro group. The stereochemistry of the spiro compounds was clearly elucidated on the basis of NMR spectra and sixteen single crystal structures.

• 出版日期2017-4-13
• 单位扬州大学