Iodocyclization/base-induced hydrodeiodination reaction of 5-substituted 4-alkenols. The influence of substituent on the stereoselective pathway
作者:Claudio Paolucci、Paolo Righi
DOI:10.1016/j.tet.2007.09.074
日期:2007.12
erythro-2-(1-iodo-2,2-dimetylpropyl)tetrahydrofuran with high stereoselectivity. The threo isomer gave clean formation of 6-tert-butyl-3,4-dihydro-2H-pyran by base-induced ring expansion, while erythro isomer underwent a base-induced ring contraction to 1-cyclopropyl-3,3-dimethylbutan-1-one. Moreover, (Z)- and (E)-5-cyclopropylpent-4-en-1-ol underwent a 6-endo-iodocyclization to threo- and erythro-2-cyclopropyl
(Z)-和(E)-5 - n-烷基取代的4-烯-1-醇的亲电碘环化反应,然后进行碱诱导的加氢碘化反应,分别在高浓度下分别立体地生成(Z)-和(E)-烷基二氢呋喃屈服。(Z)-和(E)-6,6-二甲基庚-4-en-1-ol观察到完全不同的结果:它们的碘环化分别提供了苏-和赤--2- (1-碘-2,2) -二甲基丙基)四氢呋喃具有高的立体选择性。的苏式异构体,得到纯地层6-叔丁基-3,4-二氢-2 ħ-吡喃通过碱诱导的环膨胀,而赤型异构体经历了碱诱导的环收缩为1-环丙基-3,3-二甲基丁烷-1-酮。此外,(Ž) -和(Ë)-5- cyclopropylpent -4-烯-1-醇进行了6-内-iodocyclization到苏型-和赤-2-环丙基-3- iodotetrahydro-2 ħ吡喃,分别在相同的基本处理下,以立体选择性的方式得到两个异构的6-环丙基二氢-2 H-吡喃。