Asymmetric radical cyclization reactions of axially chiral N-allyl-o-iodoanilides to form enantioenriched N-acyl dihydroindoles
作者:Dennis P. Curran、Christine H.-T. Chen、Steven J. Geib、AndreJ.B. Lapierre
DOI:10.1016/j.tet.2004.02.064
日期:2004.5
Radical cyclizations of enantiomerically enriched N-allyl-o-iodoanilides provide N-acyl-3-alkyl-2,3-dihydroindoles in good yields and with good to excellent levels of chirality transfer from the N–Ar axis to the new stereocenter. In competitive cyclizations of N-acryloyl-N-allyl-o-iodoanilides, the addition of an o-methyl group reverses the regioselectivity of the radical cyclization from the acryloyl
的自由基环化对映体富集Ñ -allyl- ö -iodoanilides提供Ñ酰基-3-烷基-2,3- dihydroindoles以良好的收率和良好的从手性转移至优秀水平Ñ -Ar轴到新立构。在N-丙烯酰基-N-烯丙基-邻碘代苯胺的竞争性环化中,邻甲基的添加使自由基环化的区域选择性从丙烯酰基转变为烯丙基。已测量了代表性自由基环化反应的近似速率常数,以提供对这些观察结果的深入了解。