Crabtree导向氢化催化剂

导向性烯烃氢化催化剂——铱催化剂：[Ir(cod)(PCy3)pyr]PF6或上图的催化剂3 {BArF=四[2,5-二(三氟甲氧基)苯基]硼}。常见的导向基团：OH, OMe, C55O, CO2Me, C(O)NR2。此催化剂由Crabtree RH最早在1979年发现。

反应实例

(1S,2S,20S)-2-Benzyl-1-methyl-1-[[20(methoxymethyl)pyrrolidinyl]-carbony1]cyclohexane (5).

A dry DCM solution (50 mL) of 4 (0.1 g, 0.3 mmol) and [Ir(cod)(py)PCy6]PF6 (0.02 g, 0.03 mmol) was stirred at r.t. for 14 h under H2 (1 atm). The mixture was concentrated in vacuum and the residue was chromatographed (hexanes:EA, 2:l) to afford 0.09 g of 5, 89% (oil).

【Schultz AG, J Am Chem Soc, 1991, 113, 4931】

[Ir(Py)(PCy3)(COD)]BArF (3). Anhydrous Pyr (1.4 mL, 17.4 mmol) was added dropwise to [Ir(COD)Cl]2 (840 mg, 1.24 mmol) in dry DCM (40 mL) under Ar till the red solution turned yellow. NaBArF (2.40 g, 2.70 mmoL) was added and the mixture was stirred at r.t. for 12 h. Filtration, concentration in vacuo and drying afforded 2 (3.02 g) as a yellow solid. To (1.354 g, 1 mmol) of 2 in dry MeOH

(40 mL) was added PCy3 (340 mg, 1.2 mmol) under Ar and the mixture was stirred at r.t. till an orange precipitate formed. Evaporation, addition of 60 mL ether and 6 mL pentane gave 3, crystals from ether.

【Pfaltz A, Adv Synth Catal, 2008, 350, 174】

【Baran PS, J Am Chem Soc, 2009, 131, 17066】

To a solution of allylic alcohol 20 (200 mg, 0.65 mmol) in CH2Cl2 (5 mL) at 23 °C was added Crabtree catalyst (156 mg, 0.19 mmol). The resulting mixture was stirred under H2 (1atm) for 12 h before it was concentrated in vacuo. Flash column chromatography (silica gel, hexanes:EtOAc 8:1) afforded hydroxy ester 21 (184 mg, 91%) as colorless oil.

【Nicolaou KC, J Am Chem Soc, 2010, 132, 8219】

相关文献

1 Crabtree RH J Organomet Chem 1979 168 183

2 Crabtree RH J Org Chem 1986 51 2655

3 Schultz AG J Am Chem Soc 1991 113 4931

4 Hoveyda AH Chem Rev 1993 93 1307

5 Pfaltz A Adv Synth Catal 2008 350 174

6 Baran PS J Am Chem Soc 2009 131 17066

7 Nicolaou KC J Am Chem Soc 2010 132 8219

编译自：Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, Page 105-106.