A process for the preparation of functional molecules using the thiol-ene coupling reaction and a process for the preparation of protected functional thiols, specifically thioesters is provided. The methods may be used to make functional polymers and other molecules. The method of making a functionalized polymer using a thiol-ene reaction comprises: providing a functionalized thioester having the following formula: wherein R is a functional group and COR′ is a protecting group; cleaving the functionalized thioester, forming a functional thiol and an acyl group; providing a polymer having a pendant vinyl group; and reacting the polymer with the functional thiol whereby a functionalized polymer is formed, wherein the functional thiol is not isolated prior to reacting with the polymer.