Neighboring Group Participation and Intramolecular Reactions

In order to make the OH into a leaving group, we must protonate it. Although at this point it could be displaced by chloride, displacement by the lone pair on sulfur to make a three-membered 

FIGURE 9.80 Retention of configuration Involving neighboring group participation. 

FIGURE 9.81 Neighboring group participation Involving sulfur. 

FIGURE 9.82 Mechanism of neighboring group participation by sulfur. 

Intramolecular reactions for three-, five-, or six-membered rings are generally faster than intermolecular reactions. 

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