Journal article
Mn-Mediated Radical-Ionic Annulations of Chiral N‑Acylhydrazones
Journal of organic chemistry, Vol.80(12), pp.6432-6440
05/20/2015
DOI: 10.1021/acs.joc.5b00863
PMID: 25992979
Abstract
Sequencing a free radical addition and nucleophilic substitution enables [3 + 2] and [4 + 2] annulations of N-acylhydrazones to afford substituted pyrrolidines and piperidines. Photolysis of alkyl iodides in the presence of Mn2(CO)10 leads to chemoselective iodine atom abstraction and radical addition to N-acylhydrazones without affecting alkyl chloride functionality. Using radical precursors or acceptors bearing a suitably positioned alkyl chloride, the radical addition is followed by further bond construction enabled by radical–polar crossover. After the alkyl radical adds to the imine bond, the resulting N-nucleophile displaces the alkyl chloride leaving group via 5-exo-tet or 6-exo-tet cyclizations, furnishing either pyrrolidine or piperidine, respectively. When both 5-exo-tet and 6-exo-tet pathways are available, the 5-exo-tet cyclization is preferred. Isolation of the intermediate radical adduct, still bearing the alkyl chloride functionality, confirms the order of events in this radical–polar crossover annulation. A chiral oxazolidinone stereocontrol element in the N-acylhydrazones provides excellent stereocontrol in these reactions.
Details
- Title: Subtitle
- Mn-Mediated Radical-Ionic Annulations of Chiral N‑Acylhydrazones
- Creators
- Kara A SlaterGregory K Friestad
- Resource Type
- Journal article
- Publication Details
- Journal of organic chemistry, Vol.80(12), pp.6432-6440
- DOI
- 10.1021/acs.joc.5b00863
- PMID
- 25992979
- NLM abbreviation
- J Org Chem
- ISSN
- 0022-3263
- eISSN
- 1520-6904
- Publisher
- American Chemical Society
- Grant note
- DOI: 10.13039/100000165, name: Division of Chemistry, award: CHE-1362111
- Language
- English
- Date published
- 05/20/2015
- Academic Unit
- Chemistry
- Record Identifier
- 9983985892402771
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