Mechanistic Study 何 龙 2009-12-26

1. Mechanistic Study 何 龙 2009-12-26

2. 内容提要 • in situ IR • NMR • MS • deuterium label • Kinetic • cirrcular dichroism spectra • Trap the intermediate • NLE

3. in situ IR 1.工作温度范围：-80—250℃ 2.工作压力范围：13mbar—350bar 3.主机测试范围：400—4800cm-1 4.分辨率：1cm-1 5.精确度：0.02cm-1 ReactIR 4000适用于实验室使用，采用傅立叶变换红外（FTIR）技术，通过测量物质的红外区域的特征“指纹”光谱，探头浸入反应物中直接测量红外吸收，可在线实时跟踪和分析反应过程，跟踪反应物、中间物和产物的瞬时变化，提供反应过程和反应组成的“实况” ,从而测定反应成分（反应物、产物及中间产物）的相对浓度变化，提供反应趋势、终点和各个过程的％转化率,得到反应机理的详细信息。

4. Enantioselective and Diastereoselective Mukaiyama-Michael Reactions Catalyzed by Bis(oxazoline) Copper(II) Complexes David A. Evans,J. Am. Chem. Soc. 2001, 123, 4480-4491

8. Dynamic Ligand Exchange of the Lanthanide Complex Leading to Structural and Functional Transformation: One-Pot Sequential Catalytic Asymmetric Epoxidation-Regioselective Epoxide-Opening Process Masakatsu Shibasaki, J. AM. CHEM. SOC. 2005, 127, 2147-2155

9. When Sm(O-i-Pr)3 (1 mol equiv) and Me3SiN3 (5 mol equiv) were mixed in THF-d8, the generation of Me3SiO-i-Pr was observed on 1H and 13C NMR spectra, suggesting that a ligand exchange occurs from the isopropoxide to the azide on the samarium metal. In situ IR experiments. (A) Me3SiN3 (20 mol equiv) + Sm(O-i-Pr)3 (1 mol equiv). Me3SiN3 (20 mol equiv) + (S)-Sm complex-1(1 mol equiv).

11. Sm(N3)3 has an absorption at 2093 cm-1 (N=N stretch). Sm(N3)2(OMe) at 2082 , SmN3(OMe)2 2083 cm-1, The broad peak at 2072 cm-1 corresponds to the samarium azide complex

12. kinetic

13. Initial Rate Kinetics on the Concentration of Catalyst [Sm(O-i-Pr)3]

15. Initial Rate Kinetics on the Concentration of Me3SiN3

18. NMR Bruker AV II-400 MHz NMR仪可进行核的动态过程、瞬变过程、反应动力学等方面的研究，是鉴定有机化合物、金属有机化合物、生物样品、高分子材料、药物等的结构、构型和构象的重要工具，还可应用与定量分析、相对分子量的测定和化学动力学等研究。

19. Scope and Mechanism of Enantioselective Michael Additions of 1,3-Dicarbonyl Compounds to Nitroalkenes Catalyzed by Nickel(II)-Diamine Complexes Dual role David A. Evans, J. AM. CHEM. SOC. 2007, 129, 11583-11592

26. This result is consistent with our kinetic studies that show that the reaction is first order in metal complex

27. Figure 7. Kinetic studies on the addition of diethyl malonate to nitrostyrene: (A) excess diethyl malonate; (B) excess nitrostyrene.

28. Proposed Reaction Mechanism

29. Hydrogen-Bonding Directed Reversal of Enantioselectivity Yong-Gui Zhou, J. AM. CHEM. SOC. 2007, 129, 750-751

33. ESI-MS Catalytic Asymmetric Epoxidation of Enones Using La-BINOL-Triphenylarsine Oxide Complex: Structural Determination of the Asymmetric Catalyst The catalytic asymmetric epoxidation of enones using the La-BINOL-Ph3AsdO complex generated from La(O-i-Pr)3, BINOL, and Ph3As=O in a ratio of 1:1:1 Masakatsu Shibasaki, J. Am. Chem. Soc. 2001, 123, 2725-2732

36. X-ray-gradecrystal from the complexes’ solution generated from La(O-i-Pr)3, BINOL, and Ph3AsdO in a ratio of 1:1:3, containing an excess amount of Ph3As=O relative to the best ratio for the asymmetric epoxidation.

39. Deductions: (i) The same complex should exist under all conditions and function as the most active and effective catalyst. (ii) The generation rate of the most active catalyst might be different in each case. (iii) Although the La-BINOL-Ph3As=O complex generated in a ratio of 1:1:1 was the best one for theepoxidation, the major component existing in the solution would be the 1:2:2 complex 7. 1:1:1 or 1:2:2

41. Figure 7. Kinetic experiments of the epoxidations using 6 mol % of the La-(R)-BINOL-Ph3AsdO complex in a ratio of 1:2:2 with x mol % of La(O-i-Pr)3.

43. Managing Highly Coordinative Substrates in Asymmetric Catalysis: A Catalytic Asymmetric Amination with a Lanthanum-Based Ternary Catalyst Masakatsu Shibasaki, J. AM. CHEM. SOC. 2009, 131, 14990–14999

45. D and L

46. oligomericLa/3a monometallic La