The cross-coupling reaction of alkenyl bromides with thiols catalyzed by palladium complexes derived from inexpensive dppf ligand is reported. These reactions occur under low catalyst loading and in high yields and display wide scope, including the coupling of bulky thiols and trisubstituted bromoolefins, and functional group tolerance. In addition, the thioetherification of less reactive chloroalkenes and, for the first time, alkenyl tosylates was accomplished using a catalyst generated from CyPF tBu alkylbisphosphine ligand.

This work describes the 6- endo - dig cyclization of S -aryl propargyl sulfides to afford 2 H -thiochromenes. The substitution at the propargylic position plays a crucial role in allowing intramolecular silver-catalyzed alkyne hydroarylation and N -iodosuccinimide-promoted iodoarylation. Additionally, a PTSA-catalyzed thiolation reaction of propargylic alcohols was developed to synthesize the required tertiary S -aryl propargyl ethers. The applicability of merging these two methods is demonstrated by synthesizing the retinoic acid receptor antagonist AGN194310.

acid−catalyzed synthesis of tetrasubstituted allenes and polysubstituted 2H-chromenes from tertiary propargylic alcohols, Tetrahedron (2019), doi:

A tandem 1,3‐sulfur migration followed by iodocyclization reaction of propargylic sulfides in the presence of NIS in HFIP has been developed to synthesize indene‐based β‐iodoalkenyl sulfides. The choice of the reaction media is crucial to promote the reaction. The proposed mechanism involving the initial NIS activation by HFIP and favoring the sulfur migration of the starting propargylic thioether via cationic intermediates is experimentally supported. In addition, the suitability of selected indene‐based β‐iodoalkenyl sulfides as building blocks for subsequent C−C bond‐forming reactions has been demonstrated.

Propargylic glycols, 2-alkynyl-1-(indol-3-yl)-1,2-diols, react with thiols undergoing a complex but selective gold-catalyzed transformation that gives rise to α-indol-3-yl α-((Z)-2-thioalkenyl) ketones. The sequence is triggered by the regioselective thiolation of indolyl diols followed by an attack of the sulfur instead of the indole over the activated alkyne. The final compounds are obtained in remarkably high yields and arise from simple starting materials such as indolyl acyloins, ethynyl magnesium bromide and thiols.