3.7- Dimethyl-3,7-Diazabicyclo nonane

Aliphatic amines, which are hard bases, are unfavorable for coordination to soft Ni°. If the principles of ligand preorganization and donor prepositioning are applied, however, (diamine)Ni° complexes are accessible, which has been demonstrated for complex (1020) with a rigid N,N -dimethyl-3,7-diazabicyclo[3.3.1 ]nonane ligand.2468... 

Ac AIBN 9-BBN Bn Boc Bu Bz CAN Cbz CD CSA DABCO DAST DBN DBU DCC DDQ DEAD DHP DIAD DIBAL-H DMAP DME DMF DMP DMSO DNB EE Ee Eq Et Fmoc GLC HLADH HMDS HMPA HOBt HPLC Im acetyl 2,2/-azobisisobutyronitrile 9-borabicyclo[3.3.1]nonane benzyl f-butoxycarbonyl butyl benzoyl ceric ammonium nitrate benzyloxycarbonyl circular dichroism camphorsulfonic acid 1.4- diazabicyclo[2.2.2]octane A,A-Diethylaminosulfur trifluoride 1.5- diazabicyclo[4.3.0]non-5-ene l,8-diazabicyclo[5.4.0]undec-7-ene A,A -dicyclohexylcarbodiimide 2.3- dichloro-5,6-dicyano-1,4-benzoquinone diethyl azodicarboxylate 3.4- dihydro-2//-pyrane diisopropyl azodicarboxylate diisobutylaluminum hydride 4-A,A -dimethylaminopyridine 1,2-dimethoxyethane A,A -dimethylformamide Dess -Martin periodinane [1,1,1 -tris(acetyloxy)-1,1 -dihydro-1,2-benziodoxol-3-( IH) -one] dimethyl sulfoxide 3.5- dinitrobenzoyl 2-ethoxyethyl enantiomeric excess molar equivalent ethyl 9-fluorenylmethoxycarbonyl gas-liquid chromatography horse liver alcohol dehydrogenase 1,1,1,3,3,3 -hexamethyldisilazane hexamethylphosphoric triamide 1 -hydroxybenzotriazole high-performance liquid chromatography 1-imidazolyl or imidazole... 

The 3,7-diazabicyclo[3.3.1]nonanes (bispidines) are among the most thoroughly investigated hetero analogs of bicyclo[3.3.1]nonane (1,2). Conformational studies of 3,7-dimethyl-3,7-diazabicyclo[3.3.1]nonane (147) in solution by the dipole moment method, and by H- and 13C-NMR spectroscopy (107,108), have shown a preference for the chair-chair conformation. Semiempirical calculations (EH, CNDO/2) (109) and analysis of the photoelectron spectrum of 147 in combination with three sets of other MO calculations (MINDO/3, MNDO, and ab initio at the STO-3G level) lead to the conclusion that, in the gas phase, 147 exists in the chair-chair conformation (108). 

THE TETRADENTATE BISPIDINE LIGAND DIMETHYL-(3,7-DIMETHYL-9-OXO-2,4-BIS(2-PYRIDYL)-3,7-DIAZABICYCLO[3.3.1]NONANE)-l,5-DICARBOXYLATE AND ITS COPPER(II) COMPLEX... 

By H-NMR spectroscopy and dipole measurements, the 3,7-dimethyl-3,7-diazabicyclo[3.3.1]nonane (dimethylbispidine) 88 was shown to adopt a cc conformation with flattened wings (108). This was later confirmed by C-NMR spectroscopy and semiempirical molecular orbital (MO) calculations (EH, CNDO/2 the double-chair form was found to be more stable than the cb isomer by --83.8kJmoP and the bb form is even more destablized (133). This preference for cc is not due to solvent or packing effects since 88 has the same conformational preference in the gas phase, as shown by a computational study, which involved a scan of the potential energy surface (PES) and the calculated... 

CDCI3, CCI4, and CS2 only a small amount of free OH groups related to the cc conformer could be detected. However, the spectra in ( 03)280 indicated, that in more polar solvents there is a competitive solute-solvent interaction, which leads to a switch from the cb to the cc form. X-ray data of 3,7-dimethyl-3,7-diazabicyclo[3.3.1]nonan-9-ol 2H20 EtOH have shown that both nitrogen atoms take part in hydrogen bonds, either with water or ethanol, and the molecule adopts a cc conformation. With IR spectroscopy of a water-free crystal, the cb conformation was assigned to the same molecule, and this is stabilized by an intramolecular N H—O bond (136). 

---