反応 #89633

反応方程式

(3R,4S)-tert-butyl 3-acetamido-4-allyl-3-(tert-butylcarbamoyl)pyrrolidine-1-carboxylate

4,4,5,5-Tetramethyl-1,3,2-dioxaborolane

→

(3R,4S)-tert-butyl 3-acetamido-3-(tert-butylcarbamoyl)-4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl)pyrrolidine-1-carboxylate

収率 82.5%

溶媒

methylene chloride

反応条件

後処理

1. 1
   その他the solution was placed in an ice bath
2. 2
   workup.WAITto reach room temperature overnight
3. 3
   その他(18 h)
4. 4
   その他The mixture was quenched with water (75 mL)
5. 5
   workup.STIRRINGstirred 15 min
6. 6
   抽出extracted with ethyl acetate (400 mL
7. 7
   洗浄The combined organic solution was washed with saturated aqueous sodium chloride (150 mL)
8. 8
   乾燥dried (MgSO4)
9. 9
   濃縮concentrated
10. 10
    その他The solid was recrystallized (2 crops) from acetonitrile

実験手順

A stirred solution of (3R,4S)-tert-butyl 3-acetamido-4-allyl-3-(tert-butylcarbamoyl)pyrrolidine-1-carboxylate (5.51 g, 15 mmol) in anhydrous methylene chloride (80 mL) under nitrogen was treated with chloro-1,5-cyclooctadiene iridium dimer (0.252 g, 0.375 mmol) and 1,2-bis(diphenylphosphino)ethane (0.299 g, 0.75 mmol), stirred for 30 min. and cooled (−20° C.). 4,4,5,5-Tetramethyl-1,3,2-dioxaborolane (3.30 mL, 22.5 mmol) was added dropwise, and the solution was placed in an ice bath and allowed to reach room temperature overnight (18 h). The mixture was quenched with water (75 mL), stirred 15 min, and extracted with ethyl acetate (400 mL, then 2×100 mL). The combined organic solution was washed with saturated aqueous sodium chloride (150 mL), dried (MgSO4), and concentrated. The solid was recrystallized (2 crops) from acetonitrile to afford (3R,4S)-tert-butyl 3-acetamido-3-(tert-butylcarbamoyl)-4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl)pyrrolidine-1-carboxylate (6.13 g, 82%) as a white solid. NMR (CDCl3) δ 6.40-6.60 (m, 1 H), 6.23 (s, 1 H), 3.95-4.05 (m, 1 H), 3.65-3.75 (m, 2 H), 2.90-3.20 (m, 2 H), 2.00 (s, 3 H), 1.45 (s, 9 H), 1.30-1.45 (m, 4 H), 1.33 (s, 9 H), 1.22 (s, 12 H), 0.70-0.80 (m, 2 H). MS (m+1): 496.4.

出典