Reaktion #89633

Reaktionsgleichung

(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

Ausbeute 82.5%

Lösungsmittel

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe solution was placed in an ice bath
2. 2
   workup.WAITto reach room temperature overnight
3. 3
   Sonstige(18 h)
4. 4
   SonstigeThe mixture was quenched with water (75 mL)
5. 5
   workup.STIRRINGstirred 15 min
6. 6
   Extraktionextracted with ethyl acetate (400 mL
7. 7
   WaschenThe combined organic solution was washed with saturated aqueous sodium chloride (150 mL)
8. 8
   Trocknendried (MgSO4)
9. 9
   Einengenconcentrated
10. 10
    SonstigeThe solid was recrystallized (2 crops) from acetonitrile

Vorschrift

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.

Quelle