Abstract Micellar solutions of cetyltrimethylammonium bromide (CTAB) surfactant allow the spirocyclization of keto‐ynamides in an aqueous medium without recourse to transition‐metal catalysis, enabling access in water to naturally‐occurring aza‐spiro compounds with potential in drug discovery. The…
Abstract An operationally simple synthesis of activated ynesulfonamides and enesulfonamides is described. Ynesulfonamides can be obtained through reaction of sulfonylamides with activated bromoalkynes and Triton B in a short time at room temperature. Likewise, terminal alkynes react with…
Abstract Two unprecedented domino reactions are described, starting from ketospiro-enesulfonamides. By treatment with ZrCl4 and allylsilane, an intramolecular electrophilic aromatic substitution and subsequent allylation is observed. By treatment with TiCl4 and allylsilane, a double enamine-type…
Abstract Natural, non-natural and ent-14β-hydroxyandrostane derivatives closely related to the cardenolide and bufadienolide skeletons were readily available through highly diastereo-/enantioselective Diels–Alder reactions calling for high pressure or Lewis acid activation. Moreover, in the…
