Total Synthesis of the Carboxylic Acid lonophore Antibiotic CP-61,405 (Routiennocin): Preparation of the Inherent Spiroketal Unit via a Reverse Coupling Process
“…For cis vinyl epoxides this outcome is reversedthe exo cis isomer is the major product. The enantiomerically pure π-allyltricarbonyliron lactone complexes prepared by Ley and co-workers are summarized in Schemes − and 59. − Finally, an enantiopure exo - π-allyltricarbonyliron lactam has recently been prepared from the corresponding cis vinyl aziridine; the complex diastereomer ratio was 18:1 (eq 6) 57 58 …”
“…For cis vinyl epoxides this outcome is reversedthe exo cis isomer is the major product. The enantiomerically pure π-allyltricarbonyliron lactone complexes prepared by Ley and co-workers are summarized in Schemes − and 59. − Finally, an enantiopure exo - π-allyltricarbonyliron lactam has recently been prepared from the corresponding cis vinyl aziridine; the complex diastereomer ratio was 18:1 (eq 6) 57 58 …”
“…Tetrahydropiranylsulfones are known to stabilize an anion when they are treated with a base. These anionic intermediates have been employed in the synthesis of many spiroketal natural compounds by Ley et al via their reaction with an adequate electrophile, sulfone group loss, and treatment under acidic conditions. Herein, we envisioned that an organometallic reagent could behave as a base and nucleophile with these compounds, making it possible to perform a domino elimination/addition reaction, as shown in Scheme .…”
Polyhydroxylated pyrrolidines have been synthesized in a one-pot procedure by the addition of an organometallic reagent to isoxazolidines obtained by a 1,3-dipolar cycloaddition between nitrones and vinylsulfones. This method highlights sulfone reactivity and provides an easy approach for the preparation of chiral pyrrolidines using cyclic imines as key intermediates.
In 1980, Sharpless and Katsuki discovered a system for the asymmetric epoxidation of primary allylic alcohols that utilizes Ti(OPr‐
i
)
4
, a dialkyl tartrate as a chiral ligand, and
tert
‐butyl hydroperoxide as the oxidant. Notably, this reaction exhibits high levels of enantioselectivity (usually > 90% ee). Like other metal‐catalyzed epoxidations, this reaction also proceeds under mild conditions with good chemical yield and with high regio‐ and chemoselectivity. Various aspects of this reaction, including its mechanism, early synthetic applications, and further transformations of the epoxy alcohol product, have been reviewed. In this chapter, the full scope and limitations of this reaction, its synthetic applications, and typical experimental conditions are described.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
