A chiral nsin ligand based on a phenyloxazoline skeleton and a preparation method and application thereof
By leveraging the synergistic effect of chiral NSiN ligands based on the phenyloxazoline skeleton with cobalt catalysts, the compatibility and stereocontrol issues of cobalt catalysts in allylic sulfonation reactions were resolved, achieving highly efficient asymmetric allylic sulfonation reactions with significantly improved yield and optical purity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU KAIRUOLI NEW MATERIAL TECH CO LTD
- Filing Date
- 2026-02-10
- Publication Date
- 2026-06-05
AI Technical Summary
Existing cobalt catalysts suffer from poor ligand-catalyst compatibility, easy catalyst deactivation, and inability to achieve efficient stereocontrol in the allyl sulfonation reaction, leading to difficulties in the asymmetric allyl sulfonation reaction.
A highly efficient synergistic catalytic reaction of allyl sulfonation was achieved using a chiral NSiN ligand based on a phenyloxazoline skeleton and a cobalt catalyst. The chiral NSiN ligand was prepared using a simple and easy-to-operate method, resulting in high reactivity and high stereoselectivity.
Highly efficient synergistic catalysis of cobalt catalyst in asymmetric allyl sulfonation reaction was achieved, with a yield of not less than 55% and an optical purity (ee value) of not less than 65%, and the ee value of some reactions can reach 90%.
Smart Images
Figure SMS_12 
Figure QLYQS_1 
Figure QLYQS_5
Abstract
Description
Technical Field
[0001] This invention relates to the field of organic synthesis technology, specifically to a chiral NSiN ligand based on a phenyloxazoline skeleton, its preparation method, and its application. Background Technology
[0002] Transition metal-catalyzed asymmetric allylic substitution reactions represent an important class of transformations for constructing chiral carbon-carbon and carbon-heteroatom bonds, with wide applications in the efficient synthesis of pharmaceuticals, natural products, and functional materials. In this field, noble metal catalysts such as palladium and iridium are well-developed and have achieved various types of highly enantioselective reactions. However, considering cost, sustainability, and unique reactivity, the use of abundant and inexpensive first-row transition metals (such as iron, cobalt, nickel, and copper) for asymmetric catalysis has become a highly attractive frontier research direction in recent years.
[0003] Cobalt, as an important member of the first-row transition metals, exhibits excellent catalytic performance in areas such as radical chemistry, CH bond activation, and reductive coupling due to its unique electronic structure and redox properties. Cobalt catalysts have also shown application potential in asymmetric allylic substitution reactions; for example, allylic functionalization can be achieved through nucleophilic attack on the π-allylic-cobalt intermediate. However, compared to the mature palladium catalytic system, the development of cobalt-catalyzed asymmetric reactions, especially allylic sulfonation reactions involving carbon-sulfur bond construction, still faces significant challenges.
[0004] Specifically, allyl sulfonation is a key step in the synthesis of chiral allyl sulfones. These structures are not only important drug skeletons and bioactive molecules, but also highly valuable synthetic intermediates. However, achieving high enantioselectivity catalysis for this reaction, especially when using cobalt catalysts, presents challenges such as poor ligand-catalyst compatibility, easy catalyst deactivation, and the inability to achieve efficient stereocontrol.
[0005] Based on this, we continue to develop a chiral ligand system that can work efficiently with cobalt catalysts and is specifically designed for catalyzing highly enantioselective allyl sulfonation reactions, thereby promoting the application of cobalt catalysts in such important asymmetric transformations. Summary of the Invention
[0006] To address the problems of poor ligand-catalyst compatibility, easy catalyst deactivation, and inability to achieve efficient stereoselectivity in the catalytic allyl sulfonation reaction of existing chiral ligands and cobalt catalysts, this invention provides a novel chiral NSiN ligand based on the phenyloxazoline skeleton, which can efficiently synergistically catalyze the allyl sulfonation reaction with cobalt catalysts, exhibiting high reactivity and high stereoselectivity.
[0007] Specifically, the following technical solutions are provided: The first aspect of this invention provides a chiral NSiN ligand based on a phenyloxazoline skeleton, the structure of which is shown in formula (I) or formula (II): , Among them, R 1 Selected from C1-C12 alkane groups, C1-C6 cycloalkyl groups, -OR w -SR w One of them; R 2 Selected from C1-C12 alkane groups, C1-C10 alkoxy groups, and C1-C10 ester groups. , , One of them; R x R x' Each of the following is selected from hydrogen, halogen, C1-C12 alkane group, C1-C10 alkoxy group, and C1-C10 ester group; R w It is selected from one of the C1-C12 alkane groups and the C1-C10 ester groups; n is an integer between 1 and 5.
[0008] Furthermore, R 1 Preferably, it is a C1-C12 alkane group or a phenyl group.
[0009] Furthermore, R 2 Preferably, it is a C1-C12 alkane group or benzyl group.
[0010] Furthermore, the chiral NSiN ligand is selected from one of the compounds shown in the following structures: , Where Me is methyl, iPr is isopropyl, tBu is tert-butyl, Bn is benzyl, and Ph is phenyl.
[0011] A second aspect of this invention provides a method for preparing the chiral NSiN ligand based on the phenyloxazoline skeleton described in the first aspect, comprising the following steps: S1, the chiral phenyl oxazoline bromide shown in formula (III) or (IV) reacts in the presence of a lithium reagent and a solvent to give the intermediate shown in formula (V) or (VI); S2, Combine the intermediate prepared in step (1) with R 1 2SiCl2 is subjected to a silylation substitution reaction in the presence of a solvent to obtain the chiral NSiN ligand shown in formula (I) or (II); The structures of equations (III) to (VI) above are shown below: , Among them, R 1 R in 2SiCl2 1 R as described in claim 1 1 Consistent; R in the structures of equations (III) to (VI) 2 R as described in claim 1 2 Consistent.
[0012] Further, in step S1, the lithium reagent is preferably one or more of n-butyllithium, tert-butyllithium, and sec-butyllithium.
[0013] Further, in step S1, the solvent is selected from one or more of the following: dry dichloromethane, diethyl ether, dibutyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, 1,4-dioxane, tetrahydrofuran, 2-methyltetrahydrofuran, toluene, xylene, benzene, chlorobenzene, fluorobenzene, chloroform, and n-hexane.
[0014] Further, in step S1, the preferred molar ratio of the chiral phenyloxazoline bromide to the lithium reagent is 1:(1-2).
[0015] Furthermore, in step S1, the reaction temperature is preferably -78~0 ℃, and the reaction time is preferably 1-4 h.
[0016] Further, in step S2, the chiral phenyloxazoline bromide reacts with R 1 The preferred molar ratio of 2SiCl2 to the feed is (1-10):1.
[0017] Furthermore, in step S2, the reaction temperature of the silanization substitution reaction is preferably 0~30 °C, and the reaction time is preferably 0.25-10 h.
[0018] The third aspect of this invention provides the application of the chiral NSiN ligand based on the phenyloxazoline skeleton described in the first aspect in asymmetric allyl substitution reactions.
[0019] Further, p-tert-butylbenzenesulfonylhydrazine and n-propyl allyl carbonate are reacted in the presence of the chiral NSiN ligand, a cobalt catalyst, and a solvent to obtain an allyl sulfone product; the structure of the allyl sulfone product is shown below: .
[0020] Furthermore, the cobalt catalyst is selected from one or more of cobalt chloride, cobalt fluoroborate, and cobalt cyclopentadiene.
[0021] Furthermore, the preferred molar ratio of p-tert-butylbenzenesulfonyl hydrazine to n-propyl allyl carbonate, chiral NSiN ligand, and cobalt catalyst is 1:(1-21):(0.01-0.1):(0.01-0.1), for example, 1:1.3:0.06:0.05.
[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a novel class of chiral NSiN ligands based on a phenyloxazoline skeleton, which can be prepared by addition reactions of chiral phenyloxazoline derivatives with different configurations and silicon dichloride derivatives. The preparation method is simple and easy to operate, and the synthetic method is applicable to a wide range of substrates, enabling the preparation of various types of optically pure chiral NSiN ligands based on the phenyloxazoline skeleton. More importantly, these novel chiral NSiN ligands can be used in asymmetric synthetic reactions, exhibiting high reactivity and high stereoselectivity in highly efficient synergistic catalysis of allyl sulfonation reactions with cobalt catalysts. Detailed Implementation
[0023] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.
[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms “comprising” or “including” used in this invention may also be replaced with the closed form “is” or “consisting of”.
[0025] The following examples relate to the preparation of chiral NSiN ligands L1-L7 based on the phenyloxazoline skeleton and their application in asymmetric synthetic reactions. The structures of chiral NSiN ligands L1-L7 are shown below: .
[0026] Example 1: This example relates to the preparation of a chiral NSiN ligand L1 based on a phenyloxazoline skeleton, as detailed below: (1) Add L-aminopropanol (120 mmol, 9.0 g), triethylamine (200 mmol, 28 mL), and 100 mL DCM to a 250 mL dry three-necked flask. Add a reflux condenser and stir at room temperature. Add 2-bromobenzoyl chloride (100 mmol, 21.9 g) dropwise. The reaction is exothermic and refluxed. After about 30 min of addition, allow the system to return to room temperature. Add triethylamine (300 mmol, 42 mL) and DMAP (5 mmol, 611 mg) to the three-necked flask. Add TsCl (150 mmol, 28.6 g) in portions. The reaction is exothermic and refluxed. After addition, let the reaction proceed overnight. Wash the reaction system once with 50 mmol of saturated ammonium chloride, once with water, and once with saturated sodium chloride. Dry the system with anhydrous sodium sulfate, filter, evaporate to dryness, and purify by column chromatography to obtain 21.6 g R. 1 It is a methyl (III) bromide, with a yield of 90%.
[0027] (2) In a 100 mL dry reaction flask, add the bromide obtained in the first step (22 mmol, 5.28 g) and 40 mL THF under a nitrogen atmosphere, and heat at -78°C. o After stirring under C for 10 minutes, add dropwise n -BuLi (24 mmol, 9.6 mL, 2.5 min hexane), continue stirring for 1 hour, add Me2SiCl2 (10 mmol, 1.29 g) dropwise, after the addition is complete, bring to room temperature for 2 hours, quench with water, extract once with EA, combine the organic phases, wash once with saturated brine, dry with anhydrous sodium sulfate, filter, evaporate to dryness and then purify by column chromatography to obtain 2.12 g L1, yield 56%. 1 H NMR (400 MHz, CDCl3) δ 7.80 (dd, J =7.7, 1.4 Hz, 2H), 7.64 (dd, J = 7.4, 1.4 Hz, 2H), 7.43 (td, J = 7.5, 1.4 Hz, 2H), 7.35 (td, J = 7.5, 1.4 Hz, 2H), 4.01 – 3.71 (m, 4H), 3.24 (t, J = 7.6Hz, 2H), 1.03 (d, J = 6.4 Hz, 6H), 0.61 (s, 6H). 13C NMR (101 MHz, CDCl3) δ163.41, 139.14, 133.58, 131.75, 128.49, 127.90, 126.86, 72.26, 60.30, 19.59.
[0028] Example 2: This example relates to the preparation of a chiral NSiN ligand L2 based on a phenyloxazoline skeleton. The preparation method is the same as in Example 1, except that an equal amount of L-valine alcohol is used to replace L-aminopropanol. All other conditions are the same. The chiral NSiN ligand L2 was prepared with a yield of 60%. 1 H NMR (400 MHz, CDCl3) δ 7.80 (dd, J = 7.6,1.4 Hz, 2H), 7.65 – 7.62 (m, 2H), 7.42 (td, J = 7.4, 1.5 Hz, 2H), 7.38 – 7.33(m, 2H), 3.81 (dd, J = 9.7, 8.2 Hz, 2H), 3.55 – 3.46 (m, 2H), 3.42 – 3.34 (m,2H), 1.51 (h, J = 6.8 Hz, 2H), 0.87 (d, J = 6.7 Hz, 6H), 0.72 (d, J = 6.7 Hz, 6H), 0.62 (s, 6H). 13 C NMR (101 MHz, CDCl3) δ 163.26, 139.32, 133.70, 131.75, 128.44, 127.84, 126.72, 71.22, 68.70, 31.34, 17.98, 17.17.
[0029] Example 3: This example relates to the preparation of a chiral NSiN ligand L3 based on a phenyloxazoline skeleton. The preparation method is the same as in Example 1, except that an equal amount of L-tert-leucine alcohol is used to replace L-aminopropanol. All other conditions are the same. The chiral NSiN ligand L3 was prepared with a yield of 55%. 1 H NMR (400 MHz, CDCl3) δ 7.81 (dd, J =7.7, 1.4 Hz, 2H), 7.63 (dd, J = 7.4, 1.5 Hz, 2H), 7.41 (td,J = 7.4, 1.5 Hz, 2H), 7.34 (td, J = 7.5, 1.5 Hz, 2H), 3.81 – 3.63 (m, 4H), 3.32 (t, J = 9.5Hz, 2H), 0.77 (s, 18H), 0.62 (s, 6H). 13 C NMR (101 MHz, CDCl3) δ 162.99,139.54, 133.81, 131.73, 128.37,127.70, 126.65, 74.56, 66.88, 32.19, 24.67.
[0030] Example 4: This example relates to the preparation of a chiral NSiN ligand L4 based on a phenyloxazoline skeleton. The preparation method is the same as in Example 1, except that an equal amount of L-phenylpropanol is used to replace L-aminopropanol, and all other conditions are the same. The chiral NSiN ligand L4 was prepared with a yield of 52%. 1 H NMR (400 MHz, CDCl3) δ 7.75 (dd, J =7.6, 1.5 Hz, 2H), 7.54 (dd, J = 7.5, 1.5 Hz, 2H), 7.32 (dtd, J = 22.8, 7.4,1.5 Hz, 4H), 7.20 – 7.06 (m, 9H), 7.05 – 6.94 (m, 4H), 3.96 – 3.77 (m, 2H), 3.65 (dd, J = 9.5, 8.3 Hz, 2H), 3.27 (t, J = 8.3 Hz, 2H), 2.84 (dd, J = 13.7, 5.4 Hz, 2H), 2.23 (dd, J = 13.8, 8.9 Hz, 2H), 0.50 (s, 6H). 13 C NMR (101 MHz, CDCl3) δ 163.71, 139.30, 137.07, 133.56, 131.60, 128.65, 127.91, 127.83,127.10, 126.79, 124.98, 76.00, 70.26, 40.07.
[0031] Example 5: This example relates to the preparation of a chiral NSiN ligand L5 based on a phenyloxazoline skeleton. The preparation method is the same as in Example 1, except that an equal amount of D-valine alcohol is used to replace L-aminopropanol. All other conditions are the same. The chiral NSiN ligand L5 was prepared with a yield of 59%. 1 H NMR (400 MHz, CDCl3) δ 7.80 (dd, J = 7.6,1.4 Hz, 2H), 7.65 – 7.62 (m, 2H), 7.42 (td, J = 7.4, 1.5 Hz, 2H), 7.39 – 7.31(m, 2H), 3.81 (dd, J = 9.7, 8.2 Hz, 2H), 3.55 – 3.45 (m, 2H), 3.42 – 3.34 (m,2H), 1.51 (h, J = 6.8 Hz, 2H), 0.87 (d, J = 6.7 Hz, 6H), 0.72 (d, J = 6.7 Hz, 6H), 0.62 (s, 6H). 13 C NMR (101 MHz, CDCl3) δ 163.26, 139.32, 133.70, 131.75, 128.44, 127.84, 126.72, 71.22, 68.70, 31.34, 17.98, 17.17.
[0032] Example 6: This example relates to the preparation of a chiral NSiN ligand L6 based on a phenyloxazoline skeleton. The preparation method is the same as in Example 1, except that: an equal amount of L-tert-leucine alcohol is used to replace L-aminopropanol, and diphenyl dichloride is used to replace Me2SiCl2. All other conditions are the same. The chiral NSiN ligand L6 was prepared with a yield of 50%. 1 H NMR (400 MHz, CDCl3) δ 8.03 (dd, J = 7.7, 1.5 Hz, 1H), 7.58 (ddd, J = 7.5, 4.9,1.6 Hz, 3H), 7.56 – 7.51 (m, 1H), 7.43 – 7.39 (m, 4H), 7.35 (dd, J = 7.9, 6.4Hz, 3H), 7.29 – 7.26 (m, 2H), 7.23 (dd,J = 7.5, 1.4 Hz, 1H), 7.17 (dd, J =5.7, 3.3 Hz, 2H), 6.86 (dd, J = 5.8, 3.4 Hz, 1H), 4.22 (dd, J = 10.0, 8.3 Hz,1H), 4.06 – 3.91 (m, 2H), 3.83 (dd, J = 11.9, 7.2 Hz, 1H), 3.58 (dd, J =11.9, 4.0 Hz, 1H), 3.22 (dd, J = 7.2, 3.9 Hz, 1H), 0.54 (d, J = 2.3 Hz, 18H). 13 C NMR (101 MHz, CDCl3) δ 171.25, 163.04, 144.06, 138.97, 138.77, 138.22,135.51, 134.84, 132.43, 130.91, 130.20, δ 129.33 (d, J = 3.4 Hz), 129.18 (d, J = 4.0 Hz), δ 127.41 (d, J = 9.2 Hz)., 126.33, 76.35, 68.49, 62.50, 34.00,33.61, 27.12, 25.37.
[0033] Example 7: This example relates to the preparation of a chiral NSiN ligand L7 based on a phenyloxazoline skeleton. The preparation method is the same as in Example 1, except that: an equal amount of L-tert-leucine alcohol is used to replace L-aminopropanol, and dibutylsilyl dichloride is used to replace Me2SiCl2. All other conditions are the same. The chiral NSiN ligand L7 was prepared with a yield of 52%. 1 H NMR (400 MHz, CDCl3) δ 7.80 (dd, J = 7.7, 1.4 Hz, 2H), 7.59 (dd, J = 7.4, 1.4 Hz, 2H), 7.42 (td, J = 7.4, 1.5 Hz, 2H), 7.34 (td, J= 7.6, 1.4 Hz, 2H), 3.91 –3.73 (m, 4H), 3.23 – 3.05 (m, 2H), 1.31 (h, J = 6.9 Hz, 4H), 1.18 (dh, J =11.5, 4.3 Hz, 8H), 1.02 (d, J = 6.2 Hz, 6H), 0.82 (t, J = 7.2 Hz, 6H). 13 C NMR (101 MHz, CDCl3) δ 164.71, 138.83, 135.44, 133.38, 129.38, 129.29, 127.89,77.27, 73.42, 61.55, 26.80, 26.64, 20.85, 14.50, 13.77.
[0034] Application example: The chiral NSiN ligands L1-L7 prepared in Examples 1-7 above, and the known ligands L8 and L9, were used in a cobalt catalyst for the synergistic catalytic allyl sulfonation reaction, as detailed below: Weigh Co(BF2) sequentially. 4• 6H₂O (5 mol%), chiral ligand L1 (6 mol%), and p-tert-butylbenzenesulfonyl hydrazine (68.5 mg, 0.3 mmol, 1.0 eq.) were added to a 15 mL sealed tube. The tube was purged three times. Under an argon atmosphere, n-propyl allyl carbonate (61.7 mg, 0.39 mmol, 1.3 eq.) and 9 mL of acetonitrile were added. The mixture was stirred at 60 °C for 12 h, filtered, and the solvent was removed by vacuum distillation. The crude product was separated by silica gel column chromatography to obtain allyl sulfone.
[0035] When the chiral ligand is the chiral NSiN ligand L1, 50.5 mg of allyl sulfone product was prepared with a yield of 70% and an ee value of 65%. 1H NMR (400 MHz, CDCl3) δ 7.68 (d, J = 2.1 Hz, 4H), 5.59 (ddd, J = 17.1,10.1, 9.5 Hz, 1H), 5.30 (dd, J = 10.2, 0.6 Hz, 1H), 5.05 (d, J = 17.1 Hz,1H), 3.49 (ddd, J = 11.3, 9.5, 3.3 Hz, 1H), 2.05 (dtd, J =10.0, 6.7, 3.3 Hz,1H), 1.71 – 1.63 (m, 1H), 1.45 (dddd, J = 12.1, 7.4, 6.0, 3.7 Hz, 1H), 1.29 –1.22 (m, 1H), 0.92 (t, J = 7.4 Hz, 3H). 13 C NMR (101 MHz, CDCl3) δ 136.4,132.1, 130.8,130.2, 128.9, 123.9, 69.9, 28.6, 19.8, 13.5. HPLC (DaicelChiralpak AD-H Column, iPrOH:n-Hexane=5.0:95.0, 1.0 mL / min), Rt = 8.11 min(major) and 9.23 min(minor), 65% ee.
[0036] When the chiral ligand is chiral NSiN ligand L2, the yield of the allyl sulfone product is 73% and the ee value is 86%.
[0037] When the chiral ligand is chiral NSiN ligand L3, the yield of the allyl sulfone product is 75% and the ee value is 90%.
[0038] When the chiral ligand is chiral NSiN ligand L4, the yield of the allyl sulfone product is 72% and the ee value is 80%.
[0039] When the chiral ligand is chiral NSiN ligand L5, the yield of the allyl sulfone product is 80%, and the ee value is 82%.
[0040] When the chiral ligand is the chiral NSiN ligand L6, the yield of the allyl sulfone product is 65% and the ee value is 84%.
[0041] When the chiral ligand is chiral NSiN ligand L7, the yield of the allyl sulfone product is 55% and the ee value is 86%.
[0042] When the chiral ligand is a known chiral ligand L8 At that time, the target product was not obtained.
[0043] When the chiral ligand is a known chiral ligand L9 At that time, the target product was not obtained.
[0044] The results of the above-mentioned synergistic catalysis of allyl sulfonation reaction using different chiral ligands and cobalt catalysts are summarized in Table 1 below: Table 1
[0045] As shown in Table 1, in the reaction system catalyzed by the cobalt catalyst for the preparation of allyl sulfone from p-tert-butylbenzenesulfonyl hydrazine and n-propyl allyl carbonate, the target product could not be obtained using the known chiral phosphine ligands L8 and L9. However, the target product could be obtained using the chiral NSiN ligands L1-L7 prepared in this invention, with a yield of not less than 55% and an ee value of not less than 65%. Among them, when using chiral ligand L3, the ee value can be as high as 90%.
[0046] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.
Claims
1. A chiral NSiN ligand based on a phenyloxazoline skeleton, characterized in that, The structure of the chiral NSiN ligand is shown in formula (I) or formula (II): ， Among them, R 1 Selected from C1-C12 alkane groups, C1-C6 cycloalkyl groups, -OR w -SR w One of them; R 2 Selected from C1-C12 alkane groups, C1-C10 alkoxy groups, and C1-C10 ester groups. , , One of them; R x R x' Each of the following is selected from hydrogen, halogen, C1-C12 alkane group, C1-C10 alkoxy group, and C1-C10 ester group; R w It is selected from one of the C1-C12 alkane groups and the C1-C10 ester groups; n is an integer between 1 and 5.
2. The chiral NSiN ligand based on the phenyloxazoline skeleton according to claim 1, characterized in that, R 1 It is a C1-C12 alkane group or phenyl group, R 2 It is a C1-C12 alkane group or benzyl group.
3. The chiral NSiN ligand based on the phenyloxazoline skeleton according to claim 1, characterized in that, The chiral NSiN ligand is selected from one of the compounds shown in the following structures: ， Where Me is methyl, iPr is isopropyl, tBu is tert-butyl, Bn is benzyl, and Ph is phenyl.
4. A method for preparing a chiral NSiN ligand based on a phenyloxazoline skeleton as described in any one of claims 1-3, characterized in that, Includes the following steps: S1, the chiral phenyl oxazoline bromide shown in formula (III) or (IV) reacts in the presence of a lithium reagent and a solvent to give the intermediate shown in formula (V) or (VI); S2, Combine the intermediate prepared in step (1) with R 1 2SiCl2 is subjected to a silylation substitution reaction in the presence of a solvent to obtain the chiral NSiN ligand shown in formula (I) or (II); The structures of equations (III) to (VI) above are shown below: ， Among them, R 1 R in 2SiCl2 1 R as described in claim 1 1 Consistent; R in the structures of equations (III) to (VI) 2 R as described in claim 1 2 Consistent.
5. The preparation method according to claim 4, characterized in that, In step S1, the lithium reagent is one or more of n-butyllithium, tert-butyllithium, and sec-butyllithium; The solvent is selected from one or more of the following: dry dichloromethane, diethyl ether, dibutyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, 1,4-dioxane, tetrahydrofuran, 2-methyltetrahydrofuran, toluene, xylene, benzene, chlorobenzene, fluorobenzene, chloroform, and n-hexane.
6. The preparation method according to claim 4, characterized in that, In step S1, the molar ratio of the chiral phenyloxazoline bromide to the lithium reagent is 1:(1-2); The reaction temperature is -78~0 ℃, and the reaction time is 1-4 h.
7. The preparation method according to claim 4, characterized in that, In step S2, the chiral phenyloxazoline bromide reacts with R 1 The molar ratio of 2SiCl2 to the feed is (1-10):1; The silanization substitution reaction is carried out at a temperature of 0–30 °C for 0.25–10 h.
8. The use of a chiral NSiN ligand based on a phenyloxazoline skeleton as described in any one of claims 1-3 in asymmetric allyl substitution reactions.
9. The application according to claim 8, characterized in that, p-tert-butylbenzenesulfonylhydrazine and n-propyl allyl carbonate were reacted in the presence of the chiral NSiN ligand, a cobalt catalyst, and a solvent to yield an allyl sulfone product; the structure of the allyl sulfone product is shown below: 。 10. The application according to claim 9, characterized in that, The cobalt catalyst is selected from one or more of cobalt chloride, cobalt fluoroborate, and cobalt cyclopentadiene. The molar ratio of p-tert-butylbenzenesulfonyl hydrazine to n-propyl allyl carbonate, chiral NSiN ligand, and cobalt catalyst is 1:(1-21):(0.01-0.1):(0.01-0.1).