10.1002/chem.201901163
The study focuses on the cross-coupling reaction (CCR) of alkenyl sulfoximines and alkenyl aminosulfoxonium salts with organozincs, facilitated by dual nickel catalysis and Lewis acid promotion. The primary chemicals utilized in this research include exocyclic, axially chiral, and acyclic alkenyl (N-methyl)sulfoximines, alkyl- and arylzincs, and Ni(dppp)Cl2 as the precatalyst. MgBr2 was employed as a promoter, and the reactions generally proceeded in ether as the solvent, although THF was also tested. The purpose of these chemicals was to investigate the CCR's effectiveness in producing stereoretentive products, which are crucial for the stereoselective synthesis of exocyclic and axially chiral alkenes. These alkenes are significant in the synthesis of medicinally important prostacyclin analogs such as iloprost, cicaprost, and inter-m-phenylene carbacyclin. The study provides insights into the stereochemical course of the CCR and its application in the synthesis of complex organic molecules with potential pharmaceutical relevance.
10.1021/jo00382a003
The research focuses on the synthesis of 5-fluoroprostacyclin, a stable and potent prostacyclin analogue, which is a significant advancement in the field due to its potential clinical applications as an inhibitor of platelet aggregation. The study aimed to overcome the limitations of prostacyclin's rapid hydration and inactivation by introducing a fluorine atom at the 5- or 7-carbon atom to achieve chemical stabilization. The process involved the reaction of protected prostacyclin derivatives with perchloryl fluoride in methanol, leading to the formation of 5-fluoro-6-methoxy derivatives. These were then separated, identified, and subjected to pyrolysis in the presence of magnesium triflate to yield 5(R)- or 5(S)-fluoro-A6-PGI2 derivatives. The study proposed a mechanism to explain the observed stereospecificity and concluded that the carbon-fluorine bond's stereoelectronic relationship with an adjacent carbonium ion is crucial in determining the product's configuration.