Curved arrows in reaction mechanism go from a positive site to a negative site.

Question

Quizplus · Accepted Answer

Curved arrows indicate the movement of electrons in a reaction mechanism, and they always go from a site of higher electron density (usually a lone pair, a pi bond, or a negatively charged atom/group) to a site of lower electron density (usually an empty orbital, a carbocation, or a positively charged atom/group). This means that the arrow will always start at a negative or electron-rich site, and end at a positive or electron-poor site.

Curved Arrows in Reaction Mechanism Go from a Positive Site