Allylation of carboxylic acids under mild conditions

Abstract

2-benzyloxy-1-methylpyridinium triflate (BnOPT) is a proven benzyl transfer reagent that is able to create benzyl esters from carboxylic acids that have been activated by a weak base. It is hypothesized that the method could be extended to transferring other resonance stabilized cations. Allyl transfer reagents based on the aforementioned benzyl transfer reagent are being investigated, namely 2-allyloxy-1-methylpyridinium triflate (AMPT) and 2-allyloxy-1- methyllepidinium triflate (AMLT). AMLT could give chemists another avenue of protection for carboxylic acids as allyl esters. These allyl groups are effective in the protection of carboxylic acids; they can withstand many possible transformations and they can be removed selectively by the use of a number of palladium-based catalysts. However, common pre-existing methods of installing allyl esters can be less selective or result in unwanted side reactions depending on what other functional groups are present on the substrate. Details of the development of the method and its efficacy on multiple substrates are presented in this thesis.