Pd-catalyzed chemo- and regioselective cross-coupling of two enamides

Different Lewis Acid Promotor-Steered Highly Regioselective Phosphorylation of Tertiary Enamides

Different Lewis acid promotor-steered highly regioselective phosphorylation of tertiary enamides with diverse H-phosphonates or H-phosphine oxides was developed. Under the catalysis of iron salt, the phosphonyl group was introduced into the α-position of tertiary enamides, affording various α-phosphorylated amides in high efficiency. On the other hand, the β-phosphorylated tertiary enamides were efficiently obtained as the products in the presence of manganese(III) acetylacetonate.

Manganese(III)-promoted highly stereoselective phosphorylation of acyclic tertiary enamides to synthesize E-selective β-phosphoryl enamides

A concise manganese(III)-promoted stereoselective β-phosphorylation of acyclic tertiary enamides and diverse H-phosphine oxides was achieved. This reaction proceeds with absolute E-selectivity in contrast to Z-selectivity obtained in other previous works and affords various E-selective β-phosphorylated tertiary enamides in high efficiency. To the best of our knowledge, this is the first case of E-selective β-phosphorylation of tertiary enamides through C-H functionalization. In addition, the method features broad substrate scope, good functional group compatibility and efficient scale-up.

Tertiary Enamides as Versatile and Valuable Substrates to Reach Chemical Diversity

Tertiary enamides display versatile reactivity and great stability compared to their enamine congeners. This review covers progress made in the development of new methods involving the enaminic reactivity of tertiary enamides with respect to the synthesis of complex nitrogen-containing compounds. A focus on the preparation of biologically active molecules is also presented. The syntheses reported herein are classified based on their reaction type. In addition, mechanistic insights are given for most of the new transformations.

1 Introduction

2 [2+2] Cycloadditions

3 [4+2] Cycloadditions

4 Electrocyclizations and Cycloisomerizations

5 Sigmatropic Rearrangements

6 Nucleophilic Additions

7 Tertiary Enamides as Electrophiles

8 Cross-Coupling Reactions

9 Tertiary-Enamide-Assisted Reactions

10 Conclusion and Perspectives

Tertiary Enamides: Versatile and Available Substrates in Synthetic Chemistry

BACKGROUND

Enamines and their variant enamides as powerful and versatile synthons have attracted great attention in synthetic chemistry. Enamides display unique stability and reduce enaminic reactivity in view of the electron-withdrawing effect of N-acyl group. A great deal of satisfactory achievements in the synthesis and application of enamides has been made in recent years. Especially, tertiary enamides without N-H bond regarded as low reactivity of compounds in the past can act as excellent nucleophiles to react with electrophiles for the construction of various nitrous molecules.

OBJECTIVE

This review focuses on recent advances on tertiary enamides in the synthetic strategies and applications including addition, coupling reaction, functionalization and electro- or photo-chemical reaction.

CONCLUSION

Tertiary enamides as electron-deficient nucleophiles display a satisfactory balance between stability and reactivity to offer multiple opportunities for the construction of various functionalized nitrogencontaining compounds. Further exploration of the reactive mechanisms involved tertiary enamides and the development of novel and efficient transformations to generate ever more complex building blocks starting from tertiary enamides are particularly worth pursuing.

Cu(OTf)2-mediated C(sp2)–H arylsulfonylation of enamides via the insertion of sulfur dioxide

A stereoselective Cu(OTf)₂-mediated C(sp²)–H sulfonylation of enamides with arylsulfonyl radicals generated in situ from DABSO and diazonium salts is developed.

Iodine-catalyzed oxidative multiple C–H bond functionalization of isoquinolines with methylarenes: an efficient synthesis of isoquinoline-1,3,4(2H)-triones

An iodine-catalyzed multiple C–H bond functionalization of isoquinolines with methylarenes via a successive benzylic sp³ C–H iodination/N-benzylation/amidation/double sp² C–H oxidation sequence to yield isoquinoline-1,3,4(2H)-triones is developed for the first time.