Alkyl oxalates are new bench-stable alcohol-activating groups for radical generation under visible light photoredox conditions. Using these precursors, the first net redox-neutral coupling of tertiary and secondary alcohols with electron-deficient alkenes is achieved.

The development of a convergent fragment coupling strategy for the enantioselective total syntheses of a group of rearranged spongian diterpenoids that harbor the cis-2,8-dioxabicyclo[3.3.0]octan-3-one unit is described. The key bond disconnection relies on a late-stage fragment coupling between a tertiary carbon radical and an electron-deficient alkene to unite two ring systems and form two new stereocenters, one of which is quaternary, in a stereoselective and efficient manner. This strategy is applied toward scalable 14-15 step syntheses of three rearranged spongian diterpenoids, cheloviolenes A and B, and dendrillolide C.

A short enantioselective synthesis of 6-substituted cis-2,8-dioxabicyclo[3.3.0]octan-3-ones is described. The pivotal step is coupling of a tertiary radical generated directly from a tertiary alcohol with a 3-chloro-5-alkoxybutenolide. This strategy is applied toward scalable 14-15 step syntheses of three rearranged spongian diterpenoids: cheloviolenes A and B and dendrillolide C.

An alkoxycarbonyl radical cyclization–cross‐coupling cascade has been developed that allows functionalized γ‐butyrolactones to be prepared in one step from simple tertiary alcohol‐derived homoallylic oxalate precursors. The reaction succeeds with aryl and vinyl electrophiles and is compatible with heterocyclic fragments in both coupling partners. This chemistry allows for the rapid construction of spirolactones, which are of interest in drug discovery endeavors.