Catalytic Halogen Bond Activation in the Benzylic C-H Bond Iodination with Iodohydantoins
Sascha H Combe1, Abolfazl Hosseini1, Lijuan Song1
1Institute of Organic Chemistry, Justus-Liebig University , Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
Abstract:
This letter presents the side-chain iodination of electron-deficient benzylic hydrocarbons at rt using N-hydroxyphthalimide (NHPI) as radical initiator and 1,3-diiodo-5,5-dimethylhydantoin and 3-iodo-1,5,5-trimethylhydantoin (3-ITMH) as iodine source. Addition of a carboxylic acid increased the reactivity due to complex formation with and activation of 3-ITMH by proton transfer and halogen bond formation. No SEAr reactions were observed under the employed reaction conditions. Our method enables convenient product isolation and gives 50-72% yields of isolated products.
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