A Synthesis of Exiguaquinol Dessulfate

Enantioselective Nickel-Catalyzed α-Spirocyclization of Lactones

Herein we report a strategy for the enantioselective synthesis of spirocycles containing all-carbon quaternary centers via nickel-catalyzed intramolecular addition of lactone enolates to aryl nitriles. The established lactone α-spirocyclization efficiently and enantioselectively forges 5-, 6-, and 7-membered rings, performing best in the synthesis of 7-membered rings (up to 90% ee). This discovery represents an expansion of the synthetic toolkit for enantioselective spirocyclization, providing access to chiral, pharmaceutically relevant spirocyclic products.

Stereocontrolled Synthesis of Enantiopure cis-Fused Octahydroisoindolones via Chiral Oxazoloisoindolone Lactams

Kinetically controlled cyclocondensation of stereoisomeric and ring-chain tautomeric mixture of (±)-hydroxylactone 1 and 0.5 equiv of (R)-phenylglycinol provided tricyclic oxazoloisoindolone lactam (3R,5aS,9aR,9bS)-2a, a versatile intermediate for further stereocontrolled transformations to access enantiopure cis-fused octahydroisoindolones. An extension of this methodology was successfully applied to the synthesis of the 5,6-dihydroxy derivative (3aR,5R,6S,7aS)-17.

Synthesis of polycyclic naphthols and naphthalenes via tandem Ti(Oi-Pr)4-promoted photoenolization Diels–Alder reaction and aromatization

An efficient approach to naphthol and naphthalene scaffolds has been developed using a sequence involving tandem Ti(Oi-Pr)₄-promoted photoenolization Diels–Alder (PEDA) and aromatization reactions.

Strategies for the Synthesis of the Halenaquinol and Xestoquinol Families of Natural Products

The halenaquinol family of naphthoquinol natural products includes a few closely related polycyclic compounds that feature an activated, electrophilic furan ring. This motif is likely responsible for the rich biological activity attributed to these secondary metabolites. Their interesting structures-related via their electrophilic furan to the biologically important furanosteroids-and their activities prompted significant efforts by organic chemists that resulted in many strategically compelling laboratory syntheses of these targets. These different strategies are compared and contrasted in this Microreview, and the authors' recent work on the structurally different but biogenetically related natural product exiguaquinol is put into the context of the previous studies on halenaquinol-type targets.