Neosporol is a natural product that includes a 1,3-dioxolane moiety , and is an isomer of sporol which has a 1,3-dioxane ring.  The total synthesis of both compounds has been reported, and each includes a step in which a dioxolane system is formed using trifluoroperacetic acid (TFPAA), prepared by the hydrogen peroxide – urea method.   This method involves no water, so it gives a completely anhydrous peracid,  necessary in this case as the presence of water would lead to unwanted side reactions . 
With longer chain length in the esters (n = 2, 3 and 4) the predominant product formed is not the lactone, but is in fact the open chain hydroxy-ester (52% yield for n = 2, 80% for n = 3 and 95% for n = 4) (path A in Scheme 3). The main reason for this would be concerned with the ease of obtaining a ring closure configuration. As already discussed, the closures are all Exo-Trig, and as such are favoured by Baldwin's rules. However, when the ring size is 6 or more atoms the distance between reactive ends is too far for easy lactone formation.
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