97040-45-4Relevant academic research and scientific papers
STUDIES ON THE CHEMISTRY OF DIOLS AND CYCLIC ETHERS-52. MECHANISM AND STEREOCHEMISTRY OF DEHYDRATION OF OXOLANES TO DIENES
Molnar, Arpad,Bartok, Mihaly
, p. 131 - 142 (1987)
On γ-Al2O3, BPO4 and NaX zeolite, the dehydration of (+/-)-2,2,3,4,5,5-hexamethyloxolane (2) in the vapour phase leads to the formation of 2,3,4,5-tetramethyl-1,5-hexadiene (8) in a slow process, while meso-2,2,3,4,5,5-hexamethyloxolane (3) is converted to 2,3,4,5-tetramethyl-2,4-hexadiene (7) with high selectivity in a fast reaction.These differences in reaction rate and selectivity indicate that the dehydration of 2 takes place by an E2 mechanism.In contrast, the steric strain in 3 results in ring opening by an E1 mechanism.These conclusions are supported by the nonselective transformations of 2,2,5,5-tetramethyloxolane (1) and 2,2,6,6-tetramethyloxane (4), and the dehydration of 1, 2 and 3 in the presence of formic acid in the liquid phase.The experimental observation prove that both the reactivity and the reaction directions in the dehydration of stereoisomeric oxolanes are determined by steric factors.
REACTIONS OF ?-ALLYL COMPLEXES OF Ti(III) WITH ALLYL, ALKYL, AND PROPARGYL ELECTROPHILES
Kasatkin, A. N.,Kulak, A. N.,Tolstikov, G. A.,Lomakina, S. I.
, p. 1875 - 1889 (2007/10/02)
The reactions of the ?-allyl complexes of Ti(III) with allyl bromides lead to the production of a mixture of cross-coupling and homocoupling products.In the case of alkyl and propargyl halides the dehalogenation products are formed.The reaction of the ?-allyl complexes of Ti(III) with allyl acetates, allyl phenyl ethers, and allyl aryl sulfones are catalyzed by Pd(PPh3)4 and give cross-coupling or elimination products, depending on the structure of the initial substrate.
Stereochemistry of Dehydration of Oxolanes to Dienes on γ-Alumina
Bartok, Michaly,Molnar, Arpad
, p. 89 - 90 (2007/10/02)
On γ-alumina gaseous (+/-)-2,2,3,4,5,5-hexamethyloxolane (1) is converted mainly into 2,3,4,5-tetramethylhexa-1,5-diene, while its meso-isomer (2) reacts at a higher rate than (1) to give 2,3,4,5-tetramethylhexa-2,4-diene with high selectivity; this is the first reported experimental observation of the stereochemistry of this dehydration reaction.
