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
Facile β-trimethylstannyl promoted 1,5-hydride shifts in cyclooctyl and cyclodecyl systems
Deuterium labelling and 2H NMR mapping demonstrate 
that cyclooctyl and cyclodecyl mesylates in aqueous EtOH exhibit greatly 
enhanced or exclusive levels of 1,5-hydride shift, provided a 
Me3Sn group is β to the migrating hydrogen, and after tin 
group loss from the formal β-stannyl cation, results in regiospecific, 
transannular alkene formation.
Conformational analysis. LXII. solvolysis and deamination studies of the 5-t-butylcylooctyl system.
Abstract The solvolyses of cis - and trans -5-t-butylcyclooctyl tosylates in acetic acid have been studied, and the rates and products are reported. The fast rate and rearranged product from the cis isomer are interpreted in terms of neighboring group participation by hydride. Improved syntheses of the compounds are given. Deamination reactions of the corresponding amines were also studied, and a product study is described and interpreted in terms of the accepted mechanism of the reaction.