Tert-butyl 5-[2-(dichloromethyl)-4(rs),5,5-trimethyl-1,3,2-dioxaborolan-4-yl]-3(rs)-methylvalerate → Tert-butyl 5-[2-(1(rs)-chloropropyl)-4(rs),5,5-trimethyl-1,3,2-dioxaborolan-4-yl]-3(rs)-methylvalerate

HRID 842407Notes

Reaction equation

Cl[CH:2]([Cl:23])[B:3]1[O:7][C:6]([CH2:9][CH2:10][CH:11]([CH3:20])[CH2:12][C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])([CH3:8])[C:5]([CH3:22])([CH3:21])[O:4]1.[CH2:24]([Mg]Br)[CH3:25]>O1CCCC1.C(OCC)(=O)C>[Cl:23][CH:2]([B:3]1[O:7][C:6]([CH2:9][CH2:10][CH:11]([CH3:20])[CH2:12][C:13]([O:15][C:16]([CH3:17])([CH3:18])[CH3:19])=[O:14])([CH3:8])[C:5]([CH3:21])([CH3:22])[O:4]1)[CH2:24][CH3:25]

Participants

Conditions

Temperature: -78 °C

Procedure

0.86 g (2.3 mmol) of tert-butyl 5-[2-(dichloromethyl)-4(RS),5,5-trimethyl-1,3,2-dioxaborolan-4-yl]-3(RS)-methylvalerate was dissolved in 5 ml of tetrahydrofuran and the solution was cooled to −78° C. under a nitrogen atmosphere. 2.6 ml (2.6 mmol) of 1M ethylmagnesium bromide in tetrahydrofuran were added dropwise, the resulting solution was stirred for 16 hours while slowly warming to room temperature and then diluted with ethyl acetate and extracted with 2M hydrochloric acid and brine. The organic phase was dried over sodium sulphate and then evporated under a vacuum to give 0.83 g of tert-butyl 5-[2-(1(RS)-chloropropyl)-4(RS),5 ,5-trimethyl-1,3 ,2-dioxaborolan-4-yl]-3(RS)-methylvalerate as an oil which was used in the next step without purification.

Workup

temperaturewhile slowly warming to room temperature
extractionextracted with 2M hydrochloric acid and brine
dry with materialThe organic phase was dried over sodium sulphate

Sources & evidence

ORD record: ord-ea12d215b0b14f199e192f4a830bf956
Source dataset: uspto-grants-2002_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06372883B1

Reaction notes

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