4- and 5-hydroxy acids can undergo acid-catalyzed intramolecular esterification to produce the corresponding lactone in good yield. Consider the following two examples of lactonization. Divide the analysis of the reaction sequences among your group. Propose reasonable mechanisms to explain the respective product formation. 

Reconvene to present your mechanisms to each other.

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Br H;C Br, CH,CI, O Na+ (Note stereochemistry!) H;C. H", H.O COH H', H.O HO ОН ÓH `CH3 (Two diastereomers) (Cis and trans isomers) 2.