4696-14-4Relevant academic research and scientific papers
Process for improving the coefficient of traction and traction drive fluid
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, (2008/06/13)
A process for improving the coefficient of traction at high temperatures in a traction drive, and a tranction drive fluid for use therein. This traction drive fluid comprises the hydrogenated product of a dimer, a trimer or a tetramer of norbornanes and/or norbornenes, and exhibits excellent traction performance over a wide temperature range from low temperature to high temperature.
Carbonium Ion Rearrangements Controlled by the Presence of a Silyl Group
Fleming, Ian,Patel, Shailesh K.,Urch, Christopher J.
, p. 115 - 124 (2007/10/02)
γ-Silyl tertiary alcohols rearrange in protic acid with 1,2-shift of hydride, phenyl, or alkyl groups, and loss of the silyl group to give alkenes.The placing of the silyl group thus controls the carbonium ion rearrangement in a preparatively useful way.Methoxycarbonyl groups do not migrate; instead, cyclopropanes are formed, except when the conformation suitable for cyclopropane formation is unattainable.When the alkene product is 2,2-disubstituted, it can be reprotonated under the reaction conditions and does not therefore always survive.This can be avoided by carrying out the reaction using a Lewis acid on the silyl ether.The starting γ-silyl alcohols are prepared by a variety of versatile methods.
Reaction of p-Nitrobenzenesulfonyl Azide with Alkylidenecycloalkanes
McManus, Samuel P.,Ortiz, Margarita,Abramovitch, Rudolph A.
, p. 336 - 342 (2007/10/02)
The 1,3-dipolar addition of p-nitrobenzenesulfonyl azide (PNBSA) to alkylidenecycloalkanes 1-3 was studied, and the products of hydrolysis were isolated and identified.The products from 1 and 2 suggest that these alkenes react to give a single triazoline intermediate.The tetrasubstituted derivatives 3, however, give both possible reaction modes.The products initially derived from 3 were the two sulfonimides expected from ring expansion (4, R=R'=Me) and methyl migration (5).Upon hydrolysis, the respective ketones, 8 and 9, were obtained in excellent overall yields.The ring-expanded sulfonimides 4 (R=R'=Me, n=6-8) were found to be less reactive under hydrolytic conditions than their respective isomers 5.Thus, subjecting the PNBSA adducts to mild hydrolysis conditions allowed the isolation of pure 9 (n=6-8).Also, in two cases (i.e., n=7,8), the pure imides 4 (R=R'=Me, n=7,8) crystallized from the hydrolysis solutions.Dipolar cycloaddition of p-nitrobenzenesulfonyl azide to 2-isopropylidenebicycloheptane followed by acid hydrolysis gives endo-2-acetyl-exo-2-methylbicycloheptane (4.1 percent), exo-2-acetyl-endo-2-methylbicycloheptane (16.3 percent), 2,2-dimethylbicyclooctan-3-one (2.1 percent), and 3,3-dimethylbicyclooctan-2-one (36.8 percent), thus providing evidence that electronic factors are much more important than steric effects in controlling regioselectivity.
CARBONIUM ION REARRANGEMENTS CONTROLLED BY THE PRESENCE OF A SILYL GROUP
Fleming, Ian,Patel, Shailesh K.
, p. 2321 - 2324 (2007/10/02)
Tertiary alcohols with a γ-silyl group (3) generally undergo a simple carbonium ion rearrangement in acid giving a single alkene product (4) with loss of the silyl group.
EPIMERIC 2-NORBORNYL CATIONS IN THE SOLVOLYSIS OF 6-exo- AND 6-endo-SUBSTITUTED 2-exo-NORBORNYL p-TOLUENESULFONATES
Grob, Cyril A.,Guenther, Bettina,Hanreich, Reinhard,Walder, Adrian
, p. 835 - 838 (2007/10/02)
Solvolysis of 6-exo- and 6-endo-substituted 2-exo-norbornyl tosylates 1 and 3, respectively, yields identical or different product mixtures depending on the inductive effect of the substituent, indicating that induction involves graded ?-participation.
