Boc-L-phenylalanine methyl ester → (3S,4S)-4-(t-Butyloxycarbonylamino)-3-hydroxy-5-phenyl-1-pentene

HRID 654308Notes

Reaction equation

HRID 654308 reaction equation
CO[C:3](=[O:20])[C@H:4]([CH2:13][C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)[NH:5][C:6]([O:8][C:9]([CH3:12])([CH3:11])[CH3:10])=[O:7].[H-].[CH2:22]([Al+]CC(C)C)[CH:23](C)C.[CH:31]([Mg]Br)=[CH2:32]>C1(C)C=CC=CC=1>[C:9]([O:8][C:6]([NH:5][C@@H:4]([CH2:13][C:14]1[CH:15]=[CH:16][CH:17]=[CH:18][CH:19]=1)[C@@H:3]([OH:20])[CH:22]=[CH2:23])=[O:7])([CH3:10])([CH3:11])[CH3:12].[C:9]([O:8][C:6]([NH:5][C@@H:4]([CH2:13][C:14]1[CH:15]=[CH:16][CH:17]=[CH:18][CH:19]=1)[C@H:3]([OH:20])[CH:31]=[CH2:32])=[O:7])([CH3:10])([CH3:11])[CH3:12]

Participants

6

Reactant 3

HCID 9882138Boc-L-phenylalanine methyl esterHCID 21225700DiisobutylaluminumhydrideHCID 178418507HCID 178418507, compound

Product 2

HCID 10468747(3S,4S)-4-(t-Butyloxycarbonylamino)-3-hydroxy-5-phenyl-1-penteneYield 54%HCID 11065740tert-butyl (2S,3R)-3-hydroxy-1-phenylpent-4-en-2-ylcarbamateYield 9%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Conditions

Temperature
0 °C

Procedure

A solution of 10.25 g (36.7 mmol) Of N-(t-butyloxycarbonyl)phenylalanine methyl ester in 60 ml of toluene was cooled to -78° C. under inert atmosphere and treated dropwise over a period of 45 min with 35 ml (52.5 mmol) of diisobutylaluminum hydride in toluene. The resulting solution was stirred for 5 min, treated with 200 ml (200 mmol) of vinylmagnesium bromide, and allowed to warm to 0° C. for 16 h. The solution was subsequently quenched cautiously with methanol, treated with aqueous Rochelle salts, stirred for a few min, and filtered. The residue was digested several times with ethyl acetate and filtered; and the combined filtrates were washed with saturated brine, dried over MgSo4, and concentrated. Silica gel chromatography using 20% ethyl acetate in hexane gave 5.46 g (54%) of the desired compound (m.p. 98°-100° C., Rf 0.19, 3:1 hexane:ethyl acetate) along with 0.92 g (9%) of (3R,4S)-4-(t-butyloxycarbonylamino)-3-hydroxy-5-phenyl-1-pentene. 1H NMR (CDCl3) δ 1.39 (s, 9 H), 2.27 (br, 1 H), 2.90 (AA', 2 H), 3.80 (m, 1 H), 4.11 (m, 1 H), 4.79 (m, 1 H), 5.19 (dt, J=11, 1.5 Hz, 1 H), 5.28 (dt, J=18, 1.5 Hz, 1 H), 5.90 (ddd, J=18, 11, 6 Hz, 1 H), 7.15-7.35 (m, 5 H). Mass spectrum: (M+H)+ =2.76.

Workup

  1. customThe solution was subsequently quenched cautiously with methanol
  2. additiontreated with aqueous Rochelle salts
  3. stirringstirred for a few min
  4. filtrationfiltered
  5. filtrationfiltered
  6. washand the combined filtrates were washed with saturated brine
  7. customdried over MgSo4
  8. concentrationconcentrated

Sources & evidence

ORD record
ord-3298754fc6554caeabf870c094a87444
Source dataset
uspto-grants-1992_07
Patent number
US05130468

Reaction notes

Loading…