Cyclic Polyolefins. XXVII. cis- and trans-Cycloöctene from N,N-Dimethylcycloöctylamine¹

Abstract

Thermal decomposition of N,N-dimethylcycloijctylamine oxide yielded cis-cycloiictene (go%), indicating that this reactio? OCCUTS by an intramolecular cyclic mechanism, with elimination of the cis-&hydrogen, forming N,N-dimethylhydroxylamine. Decomposition of N,N,N-trimethylcycloijctylammonium hydroxide formed a mixture of cis-and trans-cycloijctenes in 89% yield, which contained 60% of the trans and 40% of the cis isomer according to infrared analysis. The mixture was separated by extraction of the trans isomer with aqueous silver nitrate. Reaction of cis-cyclooctene with osmium tetroxide followed by hydrolysis of the osmic ester formed cis-1,2-cyclooctanediol, while trans-cycloijctene formed trans-l,2-cyclooctanediol. Only the cis isomers of cycloheptene and cyclohexene were formed by the amine oxide elimination and Hofmann exhaustive methylation procedures, the yields of cycloheptene being 92 and 87% and of cyclohexene 83 and 62%, respectively, by the two methods.

Raman spectra and simulation of cis‐ and trans‐cyclooctene for conformational analysis compared to inelastic neutron scattering

“…The IR spectra for these two materials in the 625–5000 cm −1 (16–2 µm) region are shown in Ref. 2. There are significant differences in the spectra of the two compounds in the 660–925 cm −1 (15–10.8 µm) region, which parallel the Raman spectral observations in this region, in which there is more intensity in the lower part of this region in the cis ‐ than in the trans ‐isomer in both spectra.…”

“…Trans ‐cyclooctene is the smallest known isolable trans ‐cycloalkene 1. This substance was first prepared in pure form by Cope et al 2 in 1953. The only structural information available for the parent material is an electron diffraction study3 that indicates a crown conformation in contrast to a chair conformation, which is expected to be ca 20 kJ/mol higher in energy.…”

Synthesis and intramolecular glycosylation of sialyl mono-esters of o-xylylene glycol. The importance of donor configuration and nitrogen protecting groups on cyclization yield and selectivity; isolation and characterization of a N-sialyl acetamide indicative of participation by acetonitrile

“…Incompatibilities between our previous allylsilane clock reaction 1–2 and the thioglycoside-based methods typically employed in sialylation reactions, 6–11 together with the absence of functionality at the 3-position, focused our attention on glycol mono-esters of the sialic acids and hence on intramolecular alcohols as nucleophiles in potential clock reactions. The predominance of the trans -configuration 12–13 and the estimated 12 kcal.mol −1 barrier to cis-trans isomerization 14 of ester linkages suggested a 4-hydroxybutyl ester, leading to an eight-membered cyclic diolide, 15–16 as the shortest alcohol-based system capable of undergoing cyclization from the ground state of the ester. Unsaturation was then added to the tether in the form of an aromatic ring to minimize transannular interactions and accelerate the cyclization, leading to the choice of the 2-hydroxymethylbenzyl esters as first generation probes.…”

Chiral Olefins as Steering Ligands in Asymmetric Catalysis

“…Starting from Zeises salt (1), complexation with a chiral amine resulted in the formation of 12. Subsequent olefin exchange with rac-(E)-cyclooctene [10] led to a pair of diastereomeric Pt complexes…”