Recent Advances in the Synthesis and Chemistry of Nitronates

Abstract

Due to their availability and versatile reactivity, nitronates have become important building blocks in the stereoselective synthesis of bioactive molecules. This short review provides a summary of recent developments on the synthesis, chemistry and applications of O-alkyl and O-silyl nitronates.1 Introduction2 Approaches to the Synthesis of Nitronates2.1 Synthesis of Six-Membered Cyclic Nitronates2.1.1 Formal [4+2] Approaches2.1.2 Formal [3+3] Approaches2.1.3 Other Approaches2.2 Synthesis of Five-Membered Cyclic Nitronates2.2.1 Formal [3+2] Approaches2.2.2 Formal [4+1] Approaches2.2.3 Oxidation Approaches3 Chemistry of Nitronates3.1 Nitronates as α-C-Nucleophiles3.2 Nitronates as α-C-Electrophiles3.3 Nitronates in [3+n]-Annulation Reactions3.4 Reactions Involving the β-Carbon Atom of Nitronates3.5 Miscellaneous Transformations4 Conclusion

α‐Electrophilic Reactivity of Nitronates

“…On the other hand, many of already known transformations are sometimes sporadic and may lack predictability, thus awaiting more investigation and generalization. Another point of growth is expected to be asymmetric catalysis that nowadays faces nitronates only occasionally ,…”

“…Resonance structures 2A and 2B easily explain the mentioned reactivity. Covalent nitronates 3 are readily available from nitro compounds and are applicable in the synthesis of various functionalized amines ,. Silyl nitronates (R’=SiAlk 3 , i. e. TMS, TBS etc.…”

Electrophilically Activated Nitroalkanes in Reactions With Carbon Based Nucleophiles

“…Processes of C-Aryl bonds formation with participation of nitroalkanes in a role of electrophilic synthon are pretty exotic. The reasons for this are summarized in our introduction and were very well-detailed in several reviews (Lalli, 2000;Smirnov et al, 2012;Tabolin et al, 2017Tabolin et al, , 2018. Arguably, one of the earliest contributions to this area was made by Fujisawa, who demonstrated interaction of nitroalkanes with organometallic reagents (Fujisawa et al, 1983).…”

C−H Reactivity of the α‐Position in Nitrones and Nitronates

“…Sixty years after this statement was made, we would like to summarize the state‐of‐art in the chemistry of azomethine N ‐oxides 1 involving reactions at their α‐carbon atom together with examples of the utility of these reactions in target‐oriented organic synthesis. Although some specific reactions of this type have been mentioned in previous reviews on the chemistry of nitrones and nitronates, the present paper is the first attempt to systemize these processes and consider azomethine N ‐oxides 1 as α‐CH‐active substrates that are similar and at the same time different from carbonyl compounds.…”