- Stabilization of long-chain intermediates in solution. octyl radicals and cations
-
The rearrangements of 1-octyl, 1-decyl and 1-tridecyl intermediates obtained from thermal lead(IV) acetate (LTA) decarboxylation of nonanoic, undecanoic and tetradecanoic acid were investigated experimentally through analysis and distribution of the products. The relationships between 1,5-, 1,6- and possibly existing 1,7-homolytic hydrogen transfer in 1-octyl-radical, as well as successive 1,2-hydride shift in corresponding cation have been computed via Monte-Carlo method. Taking into account that ratios of 1,5-/1,6-homolytic rearrangements in 1-octyl- and 1-tridecyl radical are approximately the same, the simulation shows very low involvement of 1,7-hydrogen rearrangement (1,5-/1,6-/1,7-hydrogen rearrangement = 85:31:1) in 1-octyl radical.
- Teodorovi?, Aleksandar V.,Badjuk, Dalibor M.,Stevanovi?, Nenad,Pavlovi?, Radoslav Z.
-
-
- A comparison of the activity of homogeneous tungsten and ruthenium catalysts for the metathesis of 1-octene
-
The W(O-2,6-C6H3X2)2Cl 4/Bu4Sn catalytic systems (X = Ph, F, Cl, Br) have a high activity for the metathesis of terminal alkenes and a high selectivity towards primary metathesis products. Tungsten(VI) alkoxide complexes are not nearly as active as the tungsten(VI) aryloxide complexes. Bronsted acids such as HOAc, BuOH and H2O deactivate both the W(O-2,6-C6H 3X2)2Cl4/Bu4Sn (X = Cl and Ph) catalytic systems. The Lewis base (BuOAc) showed no deactivation of the catalytic systems. The Grubbs catalyst, RuCl2(PCy3) 2(=CHPh), is very active for the metathesis of 1-alkenes, even at an alkene/Ru molar ratio = 100,000. Selectivities > 93% were generally obtained. The ruthenium catalyst is active at low temperatures (25°C) and high temperatures (130°C). It shows a high tolerance towards oxygen-containing additives. The polarity of the solvent plays a major role in the activity and also the selectivity of especially the W(O-2,6-C6H3X 2)2Cl4/Bu4Sn catalytic systems.
- Van Schalkwyk,Vosloo,Du Plessis
-
p. 781 - 788
(2007/10/03)
-
- Stereoselectivity in the Cross-metathesis of Oct-1-ene and cis- or trans-Oct-2-ene
-
The yields and the initial ratios of cis and trans geometries of non-2-ene, tridec-6-ene, or tetradec-7-ene, formed by the cross-metathesis of oct-1-ene and cis- or trans-oct-2-ene catalyzed by tungsten hexachloride-tetraphenyltin (A), hexaphenoxytungsten-ethylaluminium dichloride (B), or tungsten hexachloride-triethylaluminium (C), have been correlated to the interactions of alkyl substituents on tungstacyclobutane.The results strongly suggest that the 2,4-interaction, between the alkyl substituent on C2 and the tungsten moiety, plays an important part in determining the distribution of products.
- Uchida, Akira,Hinenoya, Masayoshi,Yamamoto, Toshihiko
-
p. 1089 - 1092
(2007/10/02)
-