Cyclododecane. Force-field calculations and proton NMR spectra of deuterated isotopomers

The crystal and molecular structure of tetrabenzocyclodecan-1,6-dione

“…The conformational properties of a large number of medium ring cycloalkanes have been determined by a combination of X-ray diffraction analysis and nmr spectroscopy, aided by strain energy calculations particularly in respect of even-membered rings; within this range of ring size a number of diversely substituted compounds has also been studied (1,2). These studies have prompted us to determine the solid state conformation of tetrabenzocyclodecan-1,6-dione 1, chosen because the carbons of the ten-membered ring in particular are all sp hybridized.…”

First Principles of Prediction of Thermodynamic Properties

“…Electron diffraction experiments have been of great aid to provide population data for cycloalkanes for gas phase samples, as reported for cycloheptane (Dillen & Geise, 1979), cyclooctane (Dorofeeva et al, 1985), cyclodecane (Hilderbrandt, Wieser & Montgomery, 1973) and cyclododecane (Atavin et al, 1989). For solution and solid state samples NMR spectroscopy have provided valuable information for temperature-dependent conformational analysis as given for cyclononane (Anet & Krane, 1980), cyclodecane (Pawar et al, 1998), cycloundecane (Brown, Pawar & Noe, 2003), and cyclododecane (Anet & Rawdah, 1978). In all these experimental investigation a population conformation with an uncertainty of ±5% was reported, and so the preferred conformation for each cycloalkane containing 7 to 12 carbon atoms precisely determined.…”

Synthèse, structure et études spectroscopiques RMN 1H et 13C de dérivés perhydrocyclododéca[b]furaniques

“…Rtactifs : a, H2S04 concentrt; b et c, Hz -nickel de Raney; d, CH3COCI dans C2HsOH; e, reactif de Jones ou chlorochrornate de pyridinium; f, Et3N; g, tosylates puis LiAIH4; h, Wolff-Kishner approximativement la symttrie D4 (figure 2). Cette conformation <<carreen, trouvee dans la structure cristalline (17), est en accord avec les donntes RMN (1 8, 19) et est celle de plus basse enthalpie calculte (20). En accord avec la litttrature (20), nos calculs effectuts a l'aide du champ empirique de forces MMX Les dtrivts tttrahydrofuraniques, comme les dtrivts cyclopentaniques (22), sont connus pour leur extrkme mobilite conformationnelle (22)(23)(24)(25), la conformation tvoluant entre deux formes extremes d'tnergies voisines (1 kcal/mol), demichaise C2 (26) et enveloppe C, (27).…”