Synthesis and Reactions of Organo Lithium, Potassium, Magnesium Compounds
|Keywords||Organomagnesium compound Lithium\Potassium guanidinates Synthesis Tishchenko reaction Catalysis|
Organomagnesium compounds containing amidinato ligand or diimino ligand are an important part of organometallic chemistry. However, compared to transition organometal compounds, related reports on the synthesis and application of such organomagnesium complexes are considerably less. What’s more, with increasingly environmental problems, development of new catalyst system for atom economic reactions has attracted great attentions.In the view of above research background, the main work of this thesis is outlined as follows:ChapterⅠ, introducion of the research background of this thesis:(1) summary of the organomagnesium compounds based on amidinate ligands and (3-diketiminato ligands; (2) an overview of the catalysts employed in Tishchenko reactions.Chapter 2, synthesis of corresponding organomagnesium compounds based on amidinate ligand,β-diketiminato ligand, orα-diimine ligand. Hitherto, what we had separated were 2a and 2b(2b) from reaction of (2-CH3C6H4)NHCHN(C6H4CH3-2) (2-2), (2,6-1Pr2C6H3)NCHCHCHNH(C6H3 1Pr2-2,6) (2-6) with MgBr2·2THF after deprotonized by "BuLi, respectively, 2c,2d,2e and 2f from that of 2-2, (3-CH3C6H4)NHCHN(C6H4CH3-3) (2-3), (3-CH3C6H4)NHCHN(C6H4CH3-4) (2-4) and 2-6 with CH3MgI, respectively, and 2g from reaction of K with the mixture of MgBr2-2THF and (2,6-Me2C6H3)NCHCHN(C6H31Pr2-2,6) (2-7), respectively. The structures of 2b,2b’,2c,2d,2e,2g were characterized by X-ray single crystal diffraction, among which 2b,2b’ and 2d were proved to be the unexpected products.Chapter 3, Catalysis of benzylaldehyde to benzyl benzoate. Lithium/potassium guanidinates prepared (3-1-3-13) were employed in catalyzing Tishchenko reaction of benzaldehyde, and the corresponding optimum reaction conditions were investigated:reaction temperature,80℃, reaction time,6 h, ratio of cat/substrate,1:100, solvent-free (for the lithium guanidinates system); reaction temperature,25℃, reaction time,12 h, ratio of cat/substrate,1:50, solvent-free (for the potassium guanidinates system). The potassium guanidinates exhibited better catalytic activities than the lithium guanidinates.