Electrocatalytic Oxidative Hydrofunctionalization Reactions of Alkenes via Co(II/III/IV) Cycle

Here we disclose a general and versatile Co(II/III/IV) electrocatalytic platform for alkene functionalization. Driven by electricity, a set of the oxidative hydrofunctionalization reactions initiated by hydrogen atom transfer were demonstrated without the need for stochiometric chemical oxidants. The scope of the reactions encompasses hydroalkoxylation, hydroacyloxylation, hydroarylation, semi-pinacol rearrangement, and deallylation. Mechanistic studies and stereochemical evidence support an ECEC process involving an electrochemically-generated organocobalt(IV) intermediate. This work presents an example of reactivity space expansion in electrocatalysis of VB12-systems by going beyond the common oxidation states of Co(I/II/III).

Total Syntheses of the C19 Diterpenoid Alkaloids (–)-Talatisamine, (–)-Liljestrandisine, and (–)-Liljestrandinine by a Fragment Coupling Approach

<p>The C19 aconitine-type diterpenoid alkaloids (–)-talatisamine, (–)-liljestrandisine, and (–)-liljestrandinine have been prepared in 31, 30, and 33 steps, respectively, from phenol. The synthetic approach features a 1,2-addition/semi-pinacol rearrangement as the key fragment coupling tactic. These efforts have also resulted in a correction to the original structure assignment of (–)-liljestrandisine.</p>

Synthesis of tricyclo[7.2.1.09,10]dodecan-11-one core ring systems of norditerpenoid alkaloids and racemulosine

A synthetic strategy involving [2 + 2] enyne cycloaddition and pinacol rearrangement to construct common BCD ring systems of norditerpenoid alkaloids and racemulosine was developed.

Flavin-Dependent Monooxygenases NotI and NotI′ Mediate Spiro-Oxindole Formation in Biosynthesis of the Notoamides

<div> <div> <div> <p>The fungal indole alkaloids are a unique class of complex molecules that have a characteristic bicyclo[2.2.2]diazaoctane ring and frequently contain a spiro-oxindole moiety. While various strains produce these compounds, an intriguing case involves the formation of individual antipodes by two unique species of fungi in the generation of the potent anticancer agents (+)- and (-)-notoamide A. NotI and NotI′ have been characterized as flavin-dependent monooxygenases that catalyze epoxidation and semi-Pinacol rearrangement to form the spiro-oxindole center within these molecules. This work elucidates a key step in the biosynthesis of the notoamides and provides an evolutionary hypothesis regarding a common ancestor for production of enantiopure notoamides. </p> </div> </div> </div>