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The enantioselective total synthesis of the rearranged spongian diterpenoid (−)‐macfarlandin C is reported. This is the first synthesis of a rearranged spongian diterpenoid in which the bulky hydrocarbon fragment is joined via a quaternary carbon to the highly hindered concave face of thecis‐2,8‐dioxabicyclo[3.3.0]octan‐3‐one moiety. The strategy involves a late‐stage fragment coupling between a tertiary carbon radical and an electrophilic butenolide resulting in the stereoselective formation of vicinal quaternary and tertiary stereocenters. A stereoselective Mukaiyama hydration that orients a pendant carboxymethyl side chaincisto the bulky octahydronapthalene substituent was pivotal in fashioning the challenging concave‐substitutedcis‐dioxabicyclo[3.3.0]octanone fragment.

 

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.

 

Recent progress in the development of photocatalytic reactions promoted by 5 visible light is leading to a renaissance in the use of photochemistry in the construction of 6 structurally elaborate organic molecules. Because of the rich functionality found in natural 7 products, studies in natural product total synthesis provide useful insights into functional 8 group compatibility of these new photocatalytic methods as well as their impact on synthetic 9 strategy. In this review, we examine total syntheses published through the end of 2020 that 10 employ a visible-light photoredox catalytic step. To assist someone interested in employing 11 the photocatalytic steps discussed, the review is organized largely by the nature of the bond 12 formed in the photocatalytic step.