Lithium iodide, reaction+ esters/pyridines

Carboxylic esters where R is methyl or ethyl can be cleaved by heating with lithium iodide in refluxing pyridine or a higher boiling amine. " The reaction is useful where a molecule is sensitive to acid and base (so that 10-10 cannot be used) or where it is desired to cleave selectively only one ester group in a molecule containing two or more. For example, refluxing O-acetyloleanolic acid methyl ester... 

The concave acids 38 and the esters 39 could be interconverted. Reaction of the acids 38 with diazomethane led to the methyl esters 39. 8 2 dealkylation of the esters 39 by lithium iodide in pyridine gave the acids 38 [27]. 

Homoconjngate addition to cyclopropanes. Corey and Fuchs have investigated the reaction of cyclopropanes with organocopper reagents as a possible synthetic route to prostanoids. For example, the tricyclic lactone ester (1) reacts with divinylcopper-lithiura (2.0 eq.) in ether at -12° (19 hr.) to give the vinylcyclopentane lactone ester (2). Tliis product was treated directly with lithium iodide (5 eq.) in pyridine (1,615-616) at reflux for 3 hr. to give the lactone (3) in about 37% yield. 

Lil in boiling pyridine or other weak nucleophilic bases can cleave alkyl esters to alkyl iodides and lithium carboxylates (Scheme 28). The reaction is mainly used for mild, aprotic cleavage of esters to car-boxylates. The high degree of dissociation for Lil and the nucleophilic strength of the iodide ion explain the reaction with esters, which is not useful with the other halides. Trimethylchlorosilane and sodium iodide also give alkyl iodides from esters. ... 

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