- Catalytic synthesis of n-alkyl arenes through alkyl group cross-metathesis
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n-Alkyl arenes were prepared in a one-pot tandem dehydrogenation/olefin metathesis/hydrogenation sequence directly from alkanes and ethylbenzene. Excellent selectivity was observed when (tBuPCP)IrH2 was paired with tungsten monoaryloxide pyrrolide complexes such as W(NAr)(C 3H6)(pyr)(OHIPT) (1a) [Ar = 2,6-i-Pr2C 6H3; pyr = pyrrolide; OHIPT = 2,6-(2,4,6-i-Pr 3C6H2)2C6H3O]. Complex 1a was also especially active in n-octane self-metathesis, providing the highest product concentrations reported to date. The thermal stability of selected olefin metathesis catalysts allowed elevated temperatures and extended reaction times to be employed.
- Dobereiner, Graham E.,Yuan, Jian,Schrock, Richard R.,Goldman, Alan S.,Hackenberg, Jason D.
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supporting information
p. 12572 - 12575
(2013/09/23)
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- ALKYLATION NON CONVENTIONNELLE DE FRIEDEL ET CRAFTS DES AROMATIQUES PAR LES ISO ET CYCLOALCANES INDUITE PAR LES CHLORURES-SELECTIVITE ET OPTIMISATION
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Friedel-Crafts alkylation of benzene by C5-C8 isoalkanes induced by tert-butyl chloride affords good yields in the presence of small amounts of AlCl3.The isomeric alkylbenzenes prepared by hydride transfer are similar to those obtained by direct alkylation from the corresponding equivalent alcohols and chlorides.The kinetic tertiary alkyl benzene rearranges to a more stable secondary isomer ; the formation of isomers discussed.Fragmentation of isoalkanes (when any) is very small except with isooctane which gives only a tert-butyl-cation.The reaction may be extended to toluene, chlorobenzene and dichlorobenzene with no major change in selectivity i.e. trans vs direct alkylation.An optimization of the reaction using dichlorobenzene increases significantly conversion and selectivity in trans-alkylation product and stresses the importance of low temperature (ca. 40 deg C) and small amounts of catalyst.
- Iraqi, A.,Gallo, R.,Phan Tan Luu, R.
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p. 548 - 554
(2007/10/02)
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