Regioselectivity of conjugate additions to monoalkyl-1,4-benzoquinones

Abstract

The regioselectivity of the reaction of conjugate addition of thiols amines, methanol and hydrogen chloride with the monoalkyl-1,4-benzoquinones avarone and 2-tert-butyl- 1,4-benzoquinone was investigated. It was shown that the regioselectivity of the reaction is influenced by the electrophilicity of position 5 in unprotonated 2-alkylquinones, the increased electrophilicity of position 6 in acidic medium, and by the acidity of the intermediate hydroquinones.

Proučavana je regioselektivnost konjugovane adicije tiola, amina, metanola i hlorovodonika na monoalkil-1,4-benzohinone avaron i 2-tert-butil-1,4-benzohinon. Pokazano je da na regioselektivnost reakcije utiču elektrofilnost položaja 5 neprotonovanih 2-alkil-hinona i povećana elektrofilnost položaja 6 u kiseloj sredini, kao i kiselost intermedijernih hidrohinona.