29779-78-0Relevant academic research and scientific papers
Sterically Crowded Cyclohexanes, 3. 4,4,8,8,12,12-Hexamethyltrispirododecane and 4,4,8,8,9,9,10,10-Octamethyldispirodecane - Two Per(cyclo)alkylated Cyclohexanes Adopting a Twistboat Conformation
Fitjer, Lutz,Scheuermann, Hans-Joerg,Klages, Ulrich,Wehle, Detlef,Stephenson, David S.,Binsch, Gerhard
, p. 1144 - 1161 (2007/10/02)
Synthesis, conformation, and dynamics of the title compounds 1 and 8 are described. 1 and -1 were obtained by sequential methylenation and cyclopropanation of 9.The hydrogenation of 1 yielded not only 7 and 8 but also 21 and 22.On the contrary, the
Synthesis, Crystal and Molecular Structure of 1,1,3,3-Bis(1',1',5',5'-tetramethylpentamethylene)allene
Irngartinger, Hermann,Kurda, Ellen,Rodewald, Hans,Berndt, Armin,Bolze, Rudolf,Schlueter, Kasper
, p. 967 - 972 (2007/10/02)
The symmetrically substituted allene derivative 1,1,3,3-bis(1',1',5',5'-tetramethylpentamethylene)allene (4) crystallizes in the monoclinic space group P21/c with Z = 4 molecules in the unit cell.The deviation of 2.4 deg from the linear arrange
Thioketene Syntheses, VI. Stable Thioketenes via Thionation of Sterically Hindered Acyl Chlorides
Schaumann, Ernst
, p. 2755 - 2765 (2007/10/02)
Sterically hindered acyl chlorides 11 are accessible via alkylation of the ester 1 or via chain elongation of the ketones 4 by one carbon atom in practicable, though multi-step reaction sequences.Action of phosphorus pentasulfide/pyridine on 11 leads to t
Structure and Isotope Effects upon the Thermal Decomposition of Carbamates of Highly Congested Tertiary Alcohols
Lomas, John S.,Thorne, Melanie P.
, p. 221 - 226 (2007/10/02)
Rate constants have been measured for the thermal decomposition in diphenyl ether at 383-433 K of the carbamates of congested tertiary aliphatic alcohols (1)-(4) which are more reactive than any carbamates previously studied.The effects of structural change among (1)-(4) or of variation in substituent at the tertiary carbon atom are inconsistent with a predominantly carbocation type of mechanism.Kinetic deuterium isotope effects (k.i.e.) upon the methyl derivatives are unambiguously primary (2.2-2.6 at 400 K) and clearly indicate extensive C-H fission in the rate-determining step.These results contrast with the previous interpretation of the k.i.e. in decompositions of CH3C6H4NHCO2But for which rate-determining C-O fission was proposed.Reinterpretation of the earlier data in terms of superimposed primary and secondary isotope effects leads to results in agreement with the new data and with the product isotope effects.Phenyl substituents, however, increase the carbocationic character of the transition state, but this mechanistic change does not cause the reactivity to be higher than that of the congested derivatives: there is, therefore no relationship between the isotope effect and the reactivity.
