A Catalytic Oxidative Quinone Heterofunctionalization Method: Synthesis of Strongylophorine-26

Unveiling Alternate Electrode Electrolysis in Electro-Photochemical and Electro-Organic Syntheses

Electro-photochemical organic synthesis is a rapidly growing field. Recently, technological advancement has contributed significantly to improve electro- and photolytic organic transformations in terms of energy efficiency and productivity. Herein, we have introduced alternating electrode electrolysis|alternate electrode electrolysis (AEE), a new technique in electrosynthesis which in combination with blue LED demonstrated an interesting three-component reaction with aryl diazoesters, 1,4-quinones, and acetone to synthesize ketal-functionalized 1,4-quinones. The AEE setup consists of two pairs of cathode-anode compared to the conventional setup of one pair. Each pair would be polarized or in a resting stage with a preset interval of choice. This would maintain a continuous potential resulting in maximum current and would facilitate the mass transport, thereby increasing the overall efficiency of the reaction. AEE offers the efficient utilization of photochemically generated carbenes. We extended AEE applications in paired photoelectrolysis reactions for the late-stage functionalization of bioactive molecules and pharmaceutical agents. As an application of AEE in electrosynthesis (without light), we demonstrated the efficient hydroxylation of fluorinated benzene and the reduction of benzonitrile to benzyl amine. The amalgamation of AEE with blue LED contributes to sustainability, and we believe that it holds great promise in the field of electro-photochemical organic synthesis.

Palladium-Catalyzed Branch- and Z-Selective Allylic C-H Amination with Aromatic Amines

Allylamines are important building blocks in the synthesis of bioactive compounds. The direct coupling of allylic C-H bonds and commonly available amines is a major synthetic challenge. An allylic C-H amination of 1,4-dienes has been accomplished by palladium catalysis. With aromatic amines, branch-selective allylic aminations are favored to generate thermodynamically unstable Z-allylamines. In addition, more basic aliphatic cyclic amines can also engage in the reaction, but linear dienyl allylic amines are the major products.

Total Synthesis of Anti-Cancer Meroterpenoids Dysideanone B and Dysiherbol A and Structural Reassignment of Dysiherbol A

The first total synthesis of marine anti-cancer meroterpenoids dysideanone B and dysiherbol A have been accomplished in a divergent way. The synthetic route features: 1) a site and stereoselective α-position alkylation of a Wieland-Miescher ketone derivative with a bulky benzyl bromide to join the terpene and aromatic moieties together and set the stage for subsequent cyclization reactions; 2) an intramolecular radical cyclization to construct the 6/6/6/6-tetracycle of dysideanone B and an intramolecular Heck reaction to forge the 6/6/5/6-fused core structure of dysiherbol A. A late-stage introduction of the ethoxy group in dysideanone B reveals that this group might come from the solvent ethanol. The structure of dysiherbol A has been revised based on our chemical total synthesis.

Regioselective Oxidative Arylation of Fluorophenols

A metal free and highly regioselective oxidative arylation reaction of fluorophenols is described. The relative position of the fluoride leaving group (i.e., ortho or para) controls the 1,2 or 1,4 nature of the arylated quinone product, lending versatility and generality to this oxidative, defluorinative, arylation concept.