27721-51-3Relevant academic research and scientific papers
Fluorine-decoupled carbon spectroscopy for the determination of configuration at fully substituted, trifluoromethyl- and perfluoroalkyl-bearing carbons: Comparison with 19F-1H heteronuclear overhauser effect spectroscopy
Mandhapati, Appi Reddy,Kato, Takayuki,Matsushita, Takahiko,Ksebati, Bashar,Vasella, Andrea,B?ttger, Erik C.,Crich, David
, p. 1754 - 1763 (2015)
The synthesis of a series of α-trifluoromethylcyclohexanols and analogous trimethylsilyl ethers by addition of the Ruppert-Prakash reagent to substituted cyclohexanones is presented. A method for the assignment of configuration of such compounds, of relat
BF3-mediated additions of organolithiums to ketimines: X-ray crystal structures of BF3-ketimine complexes
Ma, Yun,Lobkovsky, Emil,Collum, David B.
, p. 2335 - 2337 (2007/10/03)
(Chemical Equation Presented) Additions of lithium acetylides and n-BuLi to N-alkyl ketimines mediated by BF3-Et2O in THF afford hindered tert-alkylamines in moderate to good yields. Stereochemical results and crystal structures of t
Conformational Analysis and Structural Elucidation of Spirocyclic Oxaziridines Using NMR, Crystallography, and Molecular Modeling
Usuki, Yoshinosuke,Wang, Yuguang,Aube, Jeffrey
, p. 8028 - 8035 (2007/10/03)
The 1H NMR spectra of spirocyclic oxaziridines derived from substituted cyclohexanones and benzylamines were studied.Depending on substitution and on stereochemistry, these compounds often exhibit a substantial upfield shift of the cyclohexyl methylene or methine protons with a 1,3-diaxial relationship to the oxaziridine N-substituent.This effect is ascribed to a conformation that places an aromatic group over the plane of the cyclohexane ring.This conformation has also been found in the solid state by X-ray crystallography and is supported by molecular mechanics calculations.The use of the effect in assigning stereochemistry to this series of compounds is discussed.
Stereoselective Reductions of Substituted Cyclohexyl and Cyclopentyl Carbon-Nitrogen ? Systems with Hydride Reagents
Hutchins, Robert O.,Su, Wei-Yang,Sivakumar, Ramachandran,Cistone, Frank,Stercho, Yuriy P.
, p. 3412 - 3422 (2007/10/02)
Reductions of 3- and 4-substituted cyclohexyl imines, iminium salts, and enamines (via iminium ions) with various hydride reagents reveal that while small reagents (NaBH4, NaBH3CN) favor axial approach as observed with the corresponding ketones, even moderately bulky reagents (i.e., acetoxyboranes) attack preferentially from the equatorial side.This is in direct contrast to the results observed for the same reagents with the corresponding ketones and is interpreted as implying that additional steric interactions induced by the nitrogen substituents encumber axial attack by substituted hydride reagents and force approach from the equatorial direction.The very bulky tri-sec-butylborohydride anion affords highly stereodiscriminating equatorial attack.Reductions of 2-alkylcyclohexyl and 2-alkylcyclopentyl imines and enamines also proceed with high stereoselectivity to give cis-2-alkyl cyclic amines with both hindered and unhindered reagents.This is interpreted to be the result of (1) augmented steric interactions between nitrogen substituents and equatorial 2-alkyl groups (1,3-allylic strain) which induces conformational changes to favor the axial 2-alkyl conformer and (2) hindrance toward equatorial approach by reagents induced by axial alkyl substituents.The result is that equatorial approach is favored with equatorial 2-alkyl conformers and preferential axial approach with axial 2-alkyl conformers, leading to stereoselective production of cis-2-alkylamines. trans-2-n-Propyl-4-tert-butylcyclohexanone is reduced by LiBH(sec-Bu)3 preferentially from the axial direction in contrast to the usual highly selective equatorial attack observed with other cyclohexanones.
