Nickel-Catalyzed Radical Heck-Type C(sp3)-C(sp2) Coupling Cascades Enabled by Bromoalkane-Directed 1,4-Aryl Shift: Access to Olefinated Arylalanines.

A bromoalkane-directed radical 1,4-aryl shift strategy for nickel-catalyzed reductive Heck-type C(sp3)-C(sp2) coupling cascades of α-amino-ß-bromocarboxylic acid esters with α-trifluoromethyl alkenes for producing gem-difluorinated arylalanines is presented. The α-aminoalkyl radicals generated from neophyl-type aryl migration function as robust coupling partners to allow for further Giese-type addition with electron-deficient α-trifluoromethyl alkenes and vinyl sulfones, thereby realizing a new radical cascade for the simultaneous installation of an aromatic ring and olefin motif into amino acid backbones.

Total Synthesis of (±)-Cochlearol A.

Total synthesis of (±)-cochlearol A was accomplished, which features a cis 6/6 B/D ring synthesis. A TMSOTf-promoted lactonization of tert-butoxy ketoester produced the desired lactone with quaternary carbon. The cis configuration of the B/E ring is essential for regioselective B/D ring formation. Finally, simple deprotections and transformations gave cochlearol A in 16 steps from known ethyl 4-tert-butoxyacetoacetate.

Enantioselective total synthesis of (+)-Lingzhiol via tandem semipinacol rearrangement/Friedel-Crafts type cyclization.

Enantioselective total synthesis of (+)-Lingzhiol has been achieved. It is the first example of in tandem semipinacol rearrangement reactions, the migrated aryl group further reacting with the carbonyl oxonium electrophile to furnish a polycyclic skeleton. Our synthesis involves 13 steps and proceeds in 6% overall yield.

Concise synthesis of (±)-Lingzhiol via epoxy-arene cyclization.

Concise synthesis of (±)-Lingzhiol has been achieved. The key reaction involves one-step construction of a 5/5/6/6 tetra-ring backbone of Lingzhiol via epoxy-arene cyclization.