Pd/BIPHEPHOS is an Efficient Catalyst for the Pd-Catalyzed S-Allylation of Thiols with High n-Selectivity

Adv Synth Catal. 2020 Jan 23;362(2):331-336. doi: 10.1002/adsc.201901250. Epub 2019 Nov 7.

Abstract

The Pd-catalyzed S-allylation of thiols with stable allylcarbonate and allylacetate reagents offers several advantages over established reactions for the formation of thioethers. We could demonstrate that Pd/BIPHEPHOS is a catalyst system which allows the transition metal-catalyzed S-allylation of thiols with excellent n-regioselectivity. Mechanistic studies showed that this reaction is reversible under the applied reaction conditions. The excellent functional group tolerance of this transformation was demonstrated with a broad variety of thiol nucleophiles (18 examples) and allyl substrates (9 examples), and could even be applied for the late-stage diversification of cephalosporins, which might find application in the synthesis of new antibiotics.

Keywords: Tsuji-Trost allylation; crossover; isofunctional reaction; isomerization; thioether.