492-08-0, In homogeneous catalysis, the catalyst is in the same phase as the reactant. The number of collisions between reactants and catalyst is at a maximum. 492-08-0, Name is (+)-Sparteine, molecular formula is C15H26N2. In a Article，once mentioned of 492-08-0
Density functional calculations reveal that, whereas the reaction of 2-propyl-N,N-diisopropylbenzamide (6) with tBuLi in the presence of potentially tridentate donor ligands may result in lateral deprotonation of 6, the behavior of the Lewis base is non-trivial. The ability of N and O donor centers in the co-solvent to resist Li+ coordination is found to be synonymous with interaction of lithium with the formally deprotonated carbanion center. Low-energy structures have been identified whose predicted 1H and 13C NMR spectroscopic shifts are in excellent agreement with experiment. Reaction of 2-isopropyl-N,N-diisopropylbenzamide (5) with tBuLi in the presence of bidentate Lewis base N,N,N?,N?- tetramethylethylenediamine (TMEDA) yields material that is suggested by NMR spectroscopy to be laterally deprotonated and to have the formulation 5-Li laTMEDA. In spite of the tertiary aliphatic group at the 2-position in 5, X-ray crystallography reveals that the crystalline material isolated from the treatment of 5/(-)-sparteine with tBuLi is a lateral lithiate in which amide coordination and solvation by bidentate Lewis base results in the Li + ion interacting with the deprotonated alpha-C of the 2-iPr group (2.483(8) A). The tertiary carbanion center remains essentially flat and the adjacent aromatic system is highly distorted. The use of a chiral co-solvent results in two diastereomeric conformers, and their direct observation in solution suggests that interconversion is slow on the NMR timescale. Two’s company, three’s a crowd: Tridentate ligands promote tertiary carbanion formation through benzylic deprotonation. New calculations suggest that the ligands can adopt variable denticities in solution. The alternative use of bidentate ligands N,N,N?,N?-tetramethylethylenediamine and (-)-sparteine is now shown to promote benzylic reaction, accompanied by the retention of carbanion-lithium bonding (see figure). Copyright
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Reference：
Chiral nitrogen ligands in late transition metal-catalysed asymmetric synthesis—I. Addressing the problem of ligand lability in rhodium-catalysed hydrosilations,
Nitrogen-Containing Ligands for Asymmetric Homogeneous and Heterogeneous Catalysis