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Asymmetric Synthesis of gem-Difluoromethylenated Dihydroxypyrrolizidines and Indolizidines.
- Source :
-
Journal of Organic Chemistry . 10/5/2012, Vol. 77 Issue 19, p8465-8479. 15p. - Publication Year :
- 2012
-
Abstract
- An asymmetric synthesis of gem-difluoromethylenated dihydroxypyrrolizidines and indolizidines is described. The fluoride-catalyzed nucleophilic addition of PhSCF2SiMe3 (1) to chiral imides was achieved in satisfactory yields to provide mixtures of syn- and anti-isomers 6-9 with moderate to good diastereoselectivities. Reductive cleavage of the phenylsulfanyl group followed by intramolecular radical cyclization of the syn-isomers 6-9 occurred under refluxing conditions to afford the corresponding gem-difluoromethylenated 1-azabicyclic compounds 10-13 in moderate yields as a separable mixture of cis- and trans-isomers. The cis-isomers of compounds 10 and 12 and trans-13 were readily transformed to gem-difluoromethylenated dihydroxypyrrolizidines 20 and 27 and indolizidine 28, respectively, by reductive cleavage of the hydroxyl group and organometallic addition followed by hydrogenolysis. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00223263
- Volume :
- 77
- Issue :
- 19
- Database :
- Academic Search Index
- Journal :
- Journal of Organic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 82690343
- Full Text :
- https://doi.org/10.1021/jo301327s