[3 + 2] Dipolar Cycloadditions of Cyclic Nitrones with Alkenes

Abstract

The chapter describes the 1,3‐dipolar cycloadditions of cyclic nitrones with alkenes and surveys the literature from 1985 to 2014. In addition to comprehensive coverage of the cycloadditions reactions, which are presented in tables with experimental details, the introductory chapter describes methods for synthesizing cyclic nitrones, discusses mechanistic aspects of the cycloadditions and their scope, and furnishes selected examples of applications in the context of natural product synthesis.

Reductive Functionalization of Amides in Synthesis and for Modification of Bioactive Compounds

“…This class of amides, activated by an iridium complex, undergoes hydrosilylation of the carbonyl group and desilylation/elimination of the hydroxyl group to form a nitrone. The developed methodology was applied to the formation of macrocyclic nitrones ( Figure 2K ), key intermediates for the synthesis of biologically active natural products such as manzamine alkaloids (Brandi et al, 2017 ) and the β-lactam core (Stecko et al, 2014 ). Moreover, in this case, an N -silyloxyamide was used as a substrate, and a 15-membered cyclic nitrone was captured by cycloaddition with methyl acrylate to form an enantiomeric isoxazolidine.…”

Spiro‐2‐oxindoles via 1,3‐dipolar cycloadditions. A decade update

“…Huisgen's monumental work on 1,3‐dipolar cycloadditions allowed the classification of nitrones and azomethine imines as belonging to the family of azomethinium betaines [23] . Then, the behaviour of such 1,3‐dipoles was studied deeply [80–84] and the issue of cycloaddition regio‐ and stereoselectivity was rationalised in the light of the FMO theory [28,29] . To this purpose, the frontier orbitals of the parent azomethine imine predict rapid reactions with both electron‐deficient and electron‐rich monosubstituted ethylenic dipolarophiles.…”

Visible-light-promoted nitrone synthesis from nitrosoarenes under catalyst- and additive-free conditions

“…Nitrones are important synthetic building blocks in synthetic organic chemistry [1][2][3][4]. Generally, nitrones always used 1,3-dipoles to participate cycloaddition reactions to construct biologically important heterocyclic compounds [5][6][7][8][9]. In addition, nitrones can act as electrophiles to react with various nucleophiles to form N,N-disubstituted hydroxylamines [10−12] or as radical acceptors to undergo radical addition to create new chemical bonds [13,14].…”