steric

Hyperconjugation not steric repulsion leads to the staggered s ...

是老的教科提到的位阻。

As steric hindrance of the aryl amine decreased and nucleophilicity increased, occurrence of the transfor-mation reaction increased and herbicidal activity of the product decreased.

胺空间位阻越小,亲核性越强,副反越容易发生,产物除草活性越低。