反応 #1884983

反応方程式

isopropyl 2(S)-(tert-butoxycarbonylamino)-5-hydroxypentanoate

allyl methyl carbonate

BINAP

ether hexane

→

isopropyl 5-allyloxy-2(S)-(tert-butoxycarbonylamino)pentanoate

溶媒

ether

THF

反応条件

後処理

1. 1
   温度was refluxed under nitrogen for 3 hours
2. 2
   ろ過filtered through celite
3. 3
   その他evaporated
4. 4
   その他giving a dark brown syrup

実験手順

A degassed mixture of isopropyl 2(S)-(tert-butoxycarbonylamino)-5-hydroxypentanoate (product of step 26C, 17.6 g, 63.9 mmol), allyl methyl carbonate (24.0 ml, 213 mmol), Pd2(dba)3 (1.62 g, 1.78 mmol) and BINAP (4.42 g, 7.10 mmol) in THF (150 mL) was refluxed under nitrogen for 3 hours. After cooling to room temperature, the reaction was diluted with ether, filtered through celite and evaporated giving a dark brown syrup. Flash chromatography of the residue (silica gel, 30% ether/hexane) gave isopropyl 5-allyloxy-2(S)-(tert-butoxycarbonylamino)pentanoate as a viscous colorless oil, 16.3 g (81%): 1H NMR (300 MHz, Chloroform-D) δ 5.88 (ddt, 1 H, 17.4, 10.4, 5.5), 5.28 (m, 1 H), 5.22-5.11 (m, 1 H), 5.02 (sept., 1 H, J=6.2 Hz), 4.21 (br t, 1 H, J=6.7 Hz), 3.94 (dt, 2 H, J=5.9, 1.5 Hz), 3.42 (t, 2 H, J=5.9 Hz), 1.90-1.82 (m, 1 H), 1.75-1.57 (m, 3 H), 1.42 (s, 9 H), 1.21 (d, 3 H, J=6.2 Hz), 1.19 (d, 3 H, J=6.2 Hz). LCMS m/z 316 (M+H)+.

出典