Abstract
We report that pincer-ligated iridium catalysts for alkane dehydrogenation can operate in tandem with zeolite catalysts for arene-alkene coupling, to effect the overall intramolecular dehydrocoupling of alkyl-H and aryl-H bonds (i.e., the dehydrocyclization of alkyl benzene). Thus, zeolite and soluble iridium cocatalysts in refluxing pentylbenzene (205 °C) gave high yields of 1-methyl-1,2,3,4-tetrahydronaphthalene. Subsequent dehydrogenation and isomerization affords 1- and 2-methylnaphthalene and 2-methyl-1,2,3,4-tetrahydronaphthalene. Total yields of cyclized product as high as 5.4 M (94%) have been obtained, corresponding to 6800 turnovers per mol Ir. Turnover numbers for the tandem-catalyzed dehydrocyclization are much greater than those obtained for simple dehydrogenation by Ir catalysts (to give olefins) in the absence of zeolite.
Original language | English |
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Pages (from-to) | 2836-2841 |
Number of pages | 6 |
Journal | ACS Catalysis |
Volume | 6 |
Issue number | 5 |
DOIs | |
Publication status | Published - May 6 2016 |
Keywords
- C-C coupling
- C-H activation
- alkane dehydrogenation
- dehydrogenative cross-coupling
- pincer ligand
- tandem catalysis
- zeolite
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)