Palladium Catalysed Acid-Free Carboxytelomerisation of 1,3-Butadiene with Alcohols Accessing Pelargonic Acid Derivatives Including Triglycerides under Selectivity Control

Abstract

Palladium catalysed carboxytelomerisation of 1,3-butadiene with alcohols yields unsaturated C9-pelargonic esters in an atom-economic and straightforward way. Although carboxytelomerisation is of current interest, limitations of applicable alcohol substrates have not been fully investigated. In here, we present the transfer of the catalytic system comprising palladium acetate and tri-n-butyl phosphine in pyridine to a broad variety of 20 alcohols with vast difference in nucleophilicity and sterical demands yielding the corresponding esters in a 100% atom economic manner. Effects of nucleophilicity and sterical demands were revealed for monoalcohols, di- and polyols. Whilst yields, chemoselectivity and E/Z-selectivity of the pelargonic acid derivatives were excellent with up to 99%, selectivity towards mono-, di- and triesters could be controlled successfully. Finally, the reaction profile of the carboxytelomerisation glycerol was uncovered, yielding up to 97% of industrially relevant unsaturated C9-short chain fats. (Figure presented.).