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

HRID 235501Notes

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.C([Mg]Br)=C>C1(C)C=CC=CC=1>[C:9]([O:8][C:6]([NH:5][CH:4]([CH2:13][C:14]1[CH:15]=[CH:16][CH:17]=[CH:18][CH:19]=1)[CH:3]([OH:20])[CH:22]=[CH2:23])=[O:7])([CH3:10])([CH3:11])[CH3:12]

Participants

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 pure desired compound as a mixture of diastereomers.

Workup

customThe solution was subsequently quenched cautiously with methanol
additiontreated with aqueous Rochelle salts
stirringstirred for a few min
filtrationfiltered
filtrationfiltered
washand the combined filtrates were washed with saturated brine
dry with materialdried over MgSO4
concentrationconcentrated

Sources & evidence

ORD record: ord-129bdc71f2db460eaabf001921673962
Source dataset: uspto-grants-1997_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05597926

Reaction notes

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