4-(1,9a-Dihydro-2H-quinolizin-2-ylidene)morpholinium Salts from 4-(1-Methyl-3-phenyl-3-trifluoromethylsulfonyloxy-2-propenylidene)morpholinium Trifluoromethanesulfonate
- 1 January 1989
- journal article
- research article
- Published by Georg Thieme Verlag KG in Synthesis
- Vol. 1989 (10) , 735-738
- https://doi.org/10.1055/s-1989-27376
Abstract
Treatment of title triflate 1 with two equivalents of pyridine yields the 4-(4-phenyl-1,9a-dihydro-2H-quinolizin-2-ylidene)morpholinium triflate (4). Similarly, quinoline and isoquinoline convert 1 into the benzodi- hydroquinolizine salts 6 and 7, respectively. This novel access to the 1,9a- dihydro-2H-quinolizine system is based on base-initiated cyclization of a dicationic intermediate such as 4-(3-pyridiniopropenylidene) morpholinium ditriflate 2. Tertiary amines catalyze the isomerization of 4 into the 3,4-dihydroquinolizinium triflate 8.Keywords
This publication has 0 references indexed in Scilit: