Carbon-Centered Radical with Leaving Group-Mediated Ring Opening of Cyclopropenes via the Rearrangement of Cyclopropyl to the Allyl Radical: A General Access to Multisubstituted 1,3-Dienes

Abstract

We design and develop a general strategy for the assembly of multisubstituted 1,3-diene derivatives. This methodology proceeds through the cleavage of cyclopropenes via the rearrangement of the cyclopropyl radical to the allyl radical after the addition of a carbon-centered radical with a leaving group onto the strained double bond, leading to 1,3-diene products with the release of the leaving group. This approach represents a reaction mode for carbon-centered radical-mediated functionalization of cyclopropenes with ring cleavage. The transformation occurs under mild reaction conditions and shows high functional group tolerance. These highly valuable and modifiable 1,3-diene products show good antitumor activity against HCT116 cells.

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

“…Over the past two decades, our group and others have developed a transition-metal-catalyzed MCR strategy involving electrophilic trapping of onium ylides generated from metal carbenes with nucleophiles, providing an ingenious difunctionalization strategy for diazo compounds to access structurally complex and diverse molecules ( Scheme 1b , top) [ 28 – 29 ]. In recent years, radical-mediated MCRs with diazo compounds have become a highly emerging area of research and exhibit complementary reactivity to those well-developed carbene-mediated MCRs [ 30 – 42 ]. In the radical-mediated difunctionalization of alkenes, the carbon-centered radical species from a diazo compound can add to diverse alkenes followed by a diradical coupling or radical addition process to achieve the difunctionalization ( Scheme 1b , middle) [ 32 – 37 ].…”