Isothiocyanates were snythesized in a more sustainable manner by sulfurization of isocyanides with elemental sulfur using catalytic amounts of DBU (down to 2 mol%).

Thioureas are frequently used in organocatalysis and typically rely on 3,5-bis(trifluoromethyl) phenyl moieties motifs to enhance their catalytic activity. In this work, these common motifs were replaced with tailorable functional groups, such as ester or sulfone aryls, applying elemental sulfur in a multicomponent reaction (MCR) strategy for the first time for thiourea catalyst synthesis. First, several thioureas bearing aryl, benzylic or aliphatic moieties were synthesized and tested for their hydrogen bonding strength by evaluating thiourea phosphine oxide complexes via 31 P NMR and their catalytic activity in an Ugi four-component reaction (U-4CR). Finally, ester and sulfone aryl thioureas were tested in the aminolysis of propylene carbonate, leading to conversions similar to those previously reported in the literature using the 3,5-bis (trifluoromethyl)phenyl moiety, proving that these groups are suitable alternatives for the trifluoromethyl group.