Esters Cleavable by Nucleophiles

Thiol esters RC(0)SR have been prepared by nucleophilic cleavage of polystyrene-bound /V-acylsulfonamides with mixtures of a thiol and sodium thiophenolate [377] or LiBr [378], or by treatment of Wang or PAM resin bound carboxylic esters with ethanethiol in the presence of a Lewis acid (AlMe2Cl or AlMe3, DCM, 20 °C, 3 h [379,380]). The latter method can also give rise to the formation of orthoesters RC(SEt)3 and ketene thioacetals, which can, however, be hydrolyzed to the desired thiol esters by treatment with TFA [379]. 

Loaded resin Cleavage conditions Product, yield (purity) Ref. 

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