Background and overview[1]
(R)-(-)-1-[(S)-2-diphenylphosphoferroceneethyl-di-tert-butylphosphonium is a chiral ferrocene P,P ligand. Chiral ferrocene P,P ligands are important ligands in the preparation of asymmetric catalytic hydrogenation catalysts. Compared with most bisphosphine ligands that are easily oxidized, this type of bisphosphine ligands are relatively stable and are used in many drugs. It plays an important role in the synthesis of fine chemicals, such as (S)-metolachlor, jasmonate, vitamin H, alogliptin and dextromethorphan, etc. Chiral ferrocene P ,P ligands have been widely used in large-scale asymmetric catalytic hydrogenation reactions.
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Preparation[1]
Synthesis of (1)(R)-1-ferroceneethyldi-tert-butylphosphine
Under argon protection, add vinylferrocene (1mol, 212g) and (R)-3,3′-bis(3,5-dimethylphenyl)-1 to the dry reactor in sequence. , 1′-binaphthol phosphonate (0.01mol, 5.6g) and 1L toluene, then add di-tert-butylphosphine (1mol, 147g), raise the temperature to 60°C and react for 12 hours, then cool down and drop into the system Add water, then separate the layers. The organic layer is dried over anhydrous magnesium sulfate and filtered. The solvent is evaporated under reduced pressure to obtain a yellow solid. Recrystallize from dichloromethane and methanol to obtain (R)-1-ferroceneethyldi-tert-butyl. Phosphine 347g, yield 97%, e.e. value 99.5%. 31PNMR (MHz, CDCl3), δ: 48.7; 1HNMR (MHz, CDCl3), δ: 4.35-4.14 (m, 4H, Fc-H), 4.19 (m, 5H, Fc-H), 3.44 (m, 1H) ,1.83(d,J＝7.2Hz,3H),1.13(d,J＝79.6Hz,18H); HRMS: CalcdforC20H31FeP358.1513, Found358.1511; Elemental analysis measured value (calculated value)/%: C67.02( 67.05),H8.70(8.72).
Synthesis of (2)(R) initiator-(-)-1-[(S)-2-(diphenylphosphine)ferrocene]ethyl di-tert-butylphosphine
Under argon protection, add (R)-1-ferroceneethyldi-tert-butylphosphine (0.9mol, 321g) and 1L diethyl ether into the dry reactor, then add 1M diethylzinc n-Hexane solution (0.9mol, 0.9L), react at 0°C for 3 hours, add diphenylphosphine chloride (0.9mol, 199g) dropwise to the system, heat and reflux for 2 hours after the dropwise addition, add water to the system Quench and then separate the liquids. The organic layer is dried over anhydrous magnesium sulfate and filtered. The solvent is evaporated under reduced pressure to obtain a yellow solid. Recrystallize from dichloromethane and methanol to obtain (R)-(-)-1-[(S) -2-Diphenylphosphoferroceneethyl-di-tert-butylphosphonium 468g, yield 96%, e.e. value 99.3%. 31PNMR (MHz, CDCl3), δ: -26.0 (d, J=50.8Hz), 49.8 (d, J = 50.7Hz); 1HNMR (MHz, CDCl3), δ: 7.65-7.61 (m, 2H, Ph), 7.35-7.14 (m, 8H, Ph), 4.37-4.22 (m, 3H, Fc -H),3.84(s,5H,Fc-H),3.43(m,1H),1.83(m,1H),1.09(dd,J＝79.6Hz,J＝10.5Hz,18H).HRMS:CalcdforC32H40FeP2542. 1955, Found542.1192. Elemental analysis measured value (calculated value)/%: C70.82 (70.85), H7.41 (7.43).
