Dicloração seletiva e eficiente de alcenos por meio da utilização de 1,3-dicloro-5,5-dimetilhidantoina (DCDMH) e cloreto de zinco

Abstract

Halogenated organic compounds represent an important class of substances in synthetic organic chemistry due to their use in substitution and elimination reactions, among others. Although these substances are involved in a great variety of applications within the industry sector, the obtention of such compounds, especially fluorinated and chlorinated compounds has been a challenging scientific subject over the years.This work describes the synthesis of dichlorides from alkenes. The synthetic strategy involved the formation of a chloronium ion as a reaction intermetiated, which was opened afterwards by the attack of a nucleophile included in the reaction medium. To this aim, 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) was used as the electrophilic source of chlorine combined with zinc chloride as the nucleophilic source. Dichlorinated compounds were obtained with good selectivity and yields between 64 and 87%. Nine dichlorinated compounds were successfully synthesized from aliphatic or benzylalkenes at relatively short reaction times. It was observed that both substrates with high electron density and alkenes conjugated to electron withdrawing groups were effectively dichlorinated. The proposed protocol suggests the use of stable and easy-to-handle reagents, making the procedure more attractive from a practical perspective.