Steric and conformational control of the regioselectivities in the ene reaction with trisubstituted cycloalkenes: comparison of the enophiles singlet oxygen, triazolinedione, and nitrosoarene
The nitrosoarene ene reaction with the cycloalkenes 1-3 and E-4 proceeds in high twix regioselectivity to afford the hydroxylamine ene products 1a-4a (twix) and 1b-4b (twin, except far E-4 twix). Steric interactions in the enophile attack are responsible for the skew trajectory of the nitrosoarene enophile. For Z-1-methylcyclooctene (Z-4), twin abstraction dominates, caused by conformational constraints (transannular interactions) in the hydrgogen-atom abstraction. The balance between these steric and conformational factors dictates the regioselectivity in the ene reaction
Stereochemical dependence of isotope effects in the ene reaction of N-phenyl-1,2,4-triazoline-3,5-dione with isomers of butene-d3
Abstract The magnitude of the primary isotope effect of the title reaction depends on the relative stereochemistry of the competing groups, being large when the groups are cis and small when they are on opposite sides of the double bond. An intermediate such as a diaziridinium imide is required to rationalize the results.
Correlations for mass transfer between fluidized spheres and a liquid
Abstract Data on mass transfer between the solid particles and the liquid in a fluidized bed have been analyzed. After a convenient selection, various correlations have been derived. They show that for a given fluidized system, the Sherwood number is independent on the Reynolds number.