5-Aminocyclopentadienes by intramolecular addition of enolether to aminoallene functionalities
摘要:
3-(1-Alkoxyvinyl)-1-aminoallenes 6 were generated by conjugate addition of acyclic and cyclic (1-alkoxyvinyl)cuprates with the semicyclic propyne iminium salt 4. They isomerized smoothly into spiroannellated cyclopentadienes 7 through a 1,5-cyclization that in some cases occurred already at less than or equal to20degreesC. (1-Methoxyallenyl)cuprates reacted with salt 4 in a 2:1 ratio to give the 5,5-dimethoxy-4-methylenepentalene-1-spiro-2'-dihydroindole derivative 10. The thermal isomerization of morpholinoallene 12 into cyclopentadiene 13 indicates that the novel 1,5-cyclization can be extended to other 3-(1-alkoxyvinyl)-1-aminoallenes as well. (C) 2002 Elsevier Science Ltd. All rights reserved.
The 3,3-dimethylindoline-derived allenes 5 are conveniently prepared by organocuprate addition to 2-(phenylethynyl)-3,3-dimethyl-1-methylindolium triflate 4. Their thermal isomerization affords tetracyclic azepine derivatives 6. The semicyclic 2-amino 1,3-dienes 11, formed by spontaneous tautomerization of the corresponding aminoallenes, are transformed by thermal reaction into either tricyclic azepine derivatives 13 or benzothiophene-annelated azaheterocycles 14 and 15, depending on the ring size of the enamine moiety and the (hetero)aryl group at C-4 of the 2-dienamine.
Reinhard, Robert; Maas, Gerhard; Bohrisch, Joerg, Liebigs Annalen der Chemie, 1994, # 4, p. 429 - 432
5-Aminocyclopentadienes by intramolecular addition of enolether to aminoallene functionalities
作者:Robert Reinhard、Jens Schlegel、Gerhard Maas
DOI:10.1016/s0040-4020(02)01427-8
日期:2002.12
3-(1-Alkoxyvinyl)-1-aminoallenes 6 were generated by conjugate addition of acyclic and cyclic (1-alkoxyvinyl)cuprates with the semicyclic propyne iminium salt 4. They isomerized smoothly into spiroannellated cyclopentadienes 7 through a 1,5-cyclization that in some cases occurred already at less than or equal to20degreesC. (1-Methoxyallenyl)cuprates reacted with salt 4 in a 2:1 ratio to give the 5,5-dimethoxy-4-methylenepentalene-1-spiro-2'-dihydroindole derivative 10. The thermal isomerization of morpholinoallene 12 into cyclopentadiene 13 indicates that the novel 1,5-cyclization can be extended to other 3-(1-alkoxyvinyl)-1-aminoallenes as well. (C) 2002 Elsevier Science Ltd. All rights reserved.