4,4,5,5-Tetramethyl[1,3,2]dioxaborolane → 5-methoxy-1-methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole

HRID 1628016Notes

Reaction equation

I[C:2]1[C:10]2[C:5](=[CH:6][CH:7]=[C:8]([O:11][CH3:12])[CH:9]=2)[N:4]([CH3:13])[CH:3]=1.[CH3:14][C:15]1([CH3:22])[C:19]([CH3:21])([CH3:20])[O:18][BH:17][O:16]1>O1CCOCC1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.Cl[Pd]Cl.[Fe+2].C(Cl)Cl>[CH3:12][O:11][C:8]1[CH:9]=[C:10]2[C:5](=[CH:6][CH:7]=1)[N:4]([CH3:13])[CH:3]=[C:2]2[B:17]1[O:18][C:19]([CH3:21])([CH3:20])[C:15]([CH3:22])([CH3:14])[O:16]1

Participants

Conditions

Temperature: 100 °C

Procedure

The 3-iodo-5-methoxy-1-methyl-1H-indole (9.90 g, 34.5 mmol) in 1,4-dioxane (200 mL) was treated with PdCl2(dppf)-CH2Cl2 (1.41 g, 1.72 mmol), TEA (33.6 mL, 241 mmol) and 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (28.7 g, 224 mmol). The mixture was heated to about 100° C. for about 40 min. The mixture was cooled to rt and concentrated under reduced pressure. The material was stirred with EtOAc (300 mL) at rt for about 30 min and then filtered. The filtrate was concentrated under reduced pressure and the residue was purified by silica gel chromatography eluting with 100% DCM to give 5-methoxy-1-methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole (3.7 g, 37%): LC/MS (Table 2, Method a) Rt=2.68 min; MS m/z 288 (M+H)+.

Workup

temperatureThe mixture was cooled to rt
concentrationconcentrated under reduced pressure
filtrationfiltered
concentrationThe filtrate was concentrated under reduced pressure
customthe residue was purified by silica gel chromatography
washeluting with 100% DCM

Sources & evidence

ORD record: ord-94d65d28218b4939b3c2a52395f322dd
Source dataset: uspto-grants-2014_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08785639B2

Reaction notes

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