—取代联苯系电取代反应定位规则共振论观

Viewpoint of Resonance Theory of Orientation Rules in Electrophilic Substitution Reactions of Monosubstituted Biphenyls.

—取代联苯发生亲电取代反应时,当取代基为产生-I-C效应的吸电基或供电基在联苯环上4-位或2-位时,第二个取代基主要进入,未有取代基的苯环的邻位和对位,以对位为主.若取代基为产生-I>+C效应的吸电基或供电基在联苯环上3-位时,第二个取代基主要进入有取代基的苯环的邻位和对位,以对位为主.

Monosubstituted biphenyl undergoes eletrophyilic aromatic substitution reactions. Whether the first substituent is an electron-withdrawing group which has -I-C effects or an electron donating group in the 4-or-2-positions of biphenyl introduction of a second substituent occurs primarily in the unsubstituted ring in the P- and O-positions, and the main product is p-position, Whether the first substituent is an electrow-withdrawing group which has-I>+C effects or an electron-donating group in the 3-position of biphenyl, introduction of a second substituent occurs primarily in the substituted ring in the p-and-O-positions, and the main product is P-position.