Electrodimerization of N -Alkoxyamides for Zinc(II) Catalyzed Phenolic Ester Synthesis under Mild Reaction Conditions

Electrodimerization of N-Alkoxyamides for the Synthesis of Hydrazines

An efficient and valuable N-N dimerization reaction of N-alkoxyamides is reported under undivided electrolytic conditions. This electrochemical strategy provides a powerful way to access a wide range of advanced, highly functionalized hydrazines. Remarkably, an N-centered radical generated from the cleavage of the N-H bond under electrolytic conditions plays a crucial role in this transformation. Furthermore, various N-alkoxyamides bearing different substituents are suitable in this transformation, furnishing the corresponding hydrazines in up to 92% yield.

Ester dance reaction on the aromatic ring

Aromatic rearrangement reactions are useful tools in the organic chemist's toolbox when generating uncommon substitution patterns. However, it is difficult to precisely translocate a functional group in (hetero) arene systems, with the exception of halogen atoms in a halogen dance reaction. Here, we describe an unprecedented "ester dance" reaction: a predictable translocation of an ester group from one carbon atom to another on an aromatic ring. Specifically, a phenyl carboxylate substituent can be shifted from one carbon to an adjacent carbon on a (hetero) aromatic ring under palladium catalysis to often give a thermodynamically favored, regioisomeric product with modest to good conversions. The obtained ester moiety can be further converted to various aromatic derivatives through the use of classic and state-of-the-art transformations including amidation, acylations, and decarbonylative couplings.

Oxidant-free, three-component synthesis of 7-amino-6H-benzo[c]chromen-6-ones under green conditions

An oxidant-free three-component synthesis of biologically significant 7-amino-6H-benzo[c]chromen-6-ones was established involving a Sc(OTf)3 catalyzed three-component reaction between primary amines, β-ketoesters and 2-hydroxychalcones under green conditions. In this strategy, both the B and C rings of 6H-benzo[c]chromen-6-ones were constructed simultaneously starting from acyclic precursors by generating four new bonds including two C-C, one C-N and one C-O in a single synthetic operation. The mechanism of this sequential cascade process involves the initial formation of a β-enaminone intermediate followed by Michael addition with 2-hydroxychalcone, intramolecular cyclization, dehydration, lactonization and aromatization steps. Unlike the related literature approaches, this reaction delivered the products without the addition of any external oxidants to achieve the key aromatization step.