Dichloromethane → (1S,2S)-1-acetamido-N-tert-butyl-2-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl)cyclopentanecarboxamide

A stirred solution of (1S,2R)-1-acetamido-2-allyl-N-tert-butylcyclopentanecarboxamide (0.599 g, 2.25 mmol) in an anhydrous methylene chloride (9 mL) under nitrogen was treated with Ir2Cl2(COD)2 (45 mg, 0.07 mmol) and DiPhos (54 mg, 0.136 mmol) and stirred at room temperature for 30 min. 4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (0.65 mL, 4.48 mmol) was added dropwise and the solution stirred at room temperature for 20 h. The reaction mixture was poured into water (20 mL) and extracted with ethyl acetate (40 mL, then 2×15 mL), and the combined organic solution was washed with saturate aqueous sodium chloride (30 mL), dried over MgSO4, and concentrated. The residue was dissolved in minimal dichloromethane and purified by flash column chromatography (silica gel, 40-50% ethyl acetate in heptane) to afford (1S,2S)-1-acetamido-N-tert-butyl-2-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl) cyclopentanecarboxamide (0.695 g, 78%) as a white solid. 1H NMR (CDCl3, 300 MHz) δ 6.72 (br s, NH, 1 H), 5.68 (br s, NH, 1 H), 2.46-2.29 (m, 2 H), 2.10-2.19 (m, 1 H), 2.02 (s, 3 H), 2.00-1.88 (m, 1 H), 1.75-1.60 (m, 3 H), 1.52-1.38 (4 H), 1.32 (s, 9 H), 1.31 (s, 12 H), 0.81-0.70 (m, 2 H); MS (+CI): m/z for C21H39BN2O4: expected 394.3; found 395.2 (M+H)+.

1. stirringthe solution stirred at room temperature for 20 h
2. extractionextracted with ethyl acetate (40 mL
3. wash2×15 mL), and the combined organic solution was washed with saturate aqueous sodium chloride (30 mL)
4. dry with materialdried over MgSO4
5. concentrationconcentrated
6. dissolutionThe residue was dissolved in minimal dichloromethane
7. custompurified by flash column chromatography (silica gel, 40-50% ethyl acetate in heptane)

ORD record

ord-46d8db09e1b0440c98cacf2ddefd7b4b

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09440995B2