Mitsunobu卤代反应

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在Mitsunobu 反应中,用卤原子取代羟基生成卤代物也有报导,但其应用还不多见。Falck 等报导了通过Mitsunobu 过程合成一系列的卤代烃,除了氟代的产率不高以外,氯代,溴代和碘代的产率都不错。

Manna, S; Falck, J.R. Synth. Commun1985, 15, 663


 Joulle 等报导脯胺酸衍生物在经过Mitsunobu过程后得到手性翻转的碘代产物。反应首先是生成一个甲醚中间体,然后在三苯膦的作用下发生碘代,同时手性翻转。

To a flame-driedround-bottomed flask eguipped with a magnetic stir bar and an addition funnelunder N2 was added N-Boc-trans-4-hydroxy-L-proline methyl ester(19.29 g, 0.079 mol), triphenylphosphine (24.78 g, 0.094 mol) and anhydrous THF(2755 mL). The solution was cooled to 0oC. Diethyl azodicarboxylate(DEAD, 14.9 mL, 0.094 mol) in anhydrous THF (15 mL) was added dropwise,followed by the addition of methyl iodide (5.88 mL, 0.094 mol). Upon additionof MeI, the solution turned from dark brown to bright yellow. The reactionmixture was allowed to warm to ambient temperature and stirred for 10 h. Thesolvent was removed under reduced pressure and the crude oil was purified bycolumn chromatograghy, eluting with 5% EA/PE to afford the desired product as awhite solid (26.22 g, 93.8%).

Schumacher, K. K;Jiang, J; Joulle, M. M. Tetrahedron: Asymm1998, 9, 47


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