10.1016/S0040-4039(99)02175-9
The research focuses on the stereocontrolled total synthesis of (±)-dysidiolide, a marine sesterterpenoid isolated from the Caribbean sponge Dysidia etheria de Laubenfels. Dysidiolide has been shown to inhibit protein phosphatase cdc25A and the growth of certain cancer cell lines. The synthesis involves an intramolecular Diels–Alder reaction as the key step. Key chemicals used in the process include cyclohexenone, LDA (lithium diisopropylamide), vinylmagnesium bromide, thiophenol, DIBAL-H (diisobutylaluminum hydride), mCPBA (meta-chloroperoxybenzoic acid), propiolic acid, DCC (dicyclohexylcarbodiimide), DMAP (4-dimethylaminopyridine), TBDMS-Cl (tert-butyldimethylsilyl chloride), imidazole, PON-Cl (bis(dimethylamino)phosphoryl chloride), TPAP (tetrapropylammonium perruthenate), NMO (N-methylmorpholine N-oxide), and various reagents for protection and deprotection steps such as TBDMS (tert-butyldimethylsilyl) and benzyl groups. The synthesis also involves several steps of oxidation, reduction, alkylation, and cross-coupling reactions to achieve the final product.
10.1021/om300157w
The research focuses on the study of decarboxylation reactions of propiolic acids and their salts with ruthenium complexes, specifically exploring the mechanisms behind the conversion of these acids into vinylidenes under mild conditions. The purpose of this study is to understand and delineate the possible mechanisms for this reaction, which is of synthetic value in organometallic chemistry and potentially in metal-catalyzed syntheses. The research concludes that the spontaneous decarboxylation of propiolic acids or their potassium salts in the presence of ruthenium complexes leads to the formation of stable vinylidene complexes, and the lowest energy pathway for this reaction involves initial η2 coordination of the O2CC≡C? group to the ruthenium center. The study also describes the formation of several alkynyl, vinylidene, and carbene complexes from HC≡CCO2R (R = H, Me, Et) and RuCl(PP)Cp (PP = (PPh3)2, dppe), with structural determinations of some complexes supplementing earlier reports. The chemicals used in the process include propiolic acids (HC≡CCO2H and derivatives), ruthenium complexes (RuCl(PP)Cp, where PP = (PPh3)2 or dppe), and various solvents and reagents such as methanol (MeOH), tert-butanol (t-BuOH), and [NH4]PF6. Computational studies using DFT methods were employed to investigate the reaction mechanisms, providing insights into the intermediate and transition state structures involved in the decarboxylation process.
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