Versatile Catalytic Reactions of Norbornadiene Derivatives with Alkynes

Abstract

Norbornadiene andi ts derivatives are im-

Unveiling the Unexpected Reactivity of Electrophilic Diazoalkanes in [3+2] Cycloaddition Reactions within Molecular Electron Density Theory

“…The MPWB1K/6-311G (d,p) reactivity indices are gathered in Table S3 in Supplementary Material. The electronic chemical potentials µ of DAAs 7−10, µ = −3.63 (7), −4.27 (8), −4.20 (9), and −4.58 (10) eV, are lower than that of NBD 11, µ = −2.94 eV, suggesting that along a polar process the electron density will flux from NBD 11 to DAAs 7-10 via reverse electron density flux (REDF) reactions [70].…”

“…The ELF topological analysis of DAAs 7-10 shows the presence of two monosynaptic basins, V(N1) and V (N1), in 7 and one V(N1) monosynaptic basin in 8-10, integrating a total population of 3.78 e (7), 3.61 e (8), 3.58 e (9), and 3.47 e (10), associated with the non-bonding electron density on N1 nitrogen; two disynaptic basins, V(N1,N2) and V (N1, N2), integrating a total population of 3.74 e (7), 3.88 e (8), 3.90 e (9), and 3.97 e (10), associated with the N1-N2 double bond; and one V(C3,N2) disynaptic basin, integrating 3.01 e (7), 2.90 e (9), 2.88 e (9), and 2.82 e (10), associated with the C3-N2 overpopulated single bond, which shows the influence of substitution on the electronic distribution of the N1-N2-C3 moiety of these DAAs. Finally, the presence of two monosynaptic basins, V(C3) and V (C3), integrating a total of 0.92 e (7), 0.92 e (8), 0.88 e (9), and 0.98 e (10), associated with a pseudoradical center at C3, classifies the DAAs 7-10 as pseudo(mono)radical TACs, thus suggesting their participation in pmr-type 32CA reactions [36].…”

“…Recently, NBD has also found applications in molecular photoswitches to absorb solar radiation [5], and by 2018, more than 30 thousand publications and patents had reported their production and applications in various fields [1]. The behavior of NBD derivatives in the Wagner-Meerwein rearrangement [6,7], photochemical di-π methane rearrangement [8], Diels Alder reactions [9], catalytic reactions with alkynes [10] and several other instances [1] have established their uniqueness as organic reagents and fostered their wide synthetic applications in [3+2] cycloaddition (32CA) reactions to form isoxazolidines, triazoles, carbocycles and other heterocycles of biological and environmental relevance [11][12][13][14][15]. In 2001, Tam and coworkers [16,17] reported the highly regio-and stereoselective intramolecular 32CA reactions of NBD-tethered nitrones and nitrile oxides (Scheme 1).…”

Transition Metal/Lewis Acid Co‐Catalyzed Ring‐Opening Reactions of Oxa/Azabenzonorbornadienes

“…They undergo various kinds of reactions such as cyclization, alkynylation, ring‐opening reactions, cycloaddition reaction and other tandem reactions. Transition metals were mainly used as the only catalyst for the reactions . The ring‐opening reaction of oxa/azabenzonorbornadienes is one of the most important transformations as it leads to the development of molecular skeleton of biological importance.…”

Unveiling the Unexpected Reactivity of Electrophilic Diazoalkanes in [3+2] Cycloaddition Reactions within Molecular Electron Density Theory

“…Recently, NBD has also found applications in molecular photoswitches to absorb solar radiation [5] and, by 2018, more than 30 thousand publications and patents had reported their production and applications in various fields [1]. The behavior of NBD derivatives in the Wagner-Meerwin rearrangement [6,7], photochemical di-π methane rearrangement [8], Diels Alder reactions [9], catalytic reactions with alkynes [10] and several other instances [1] have established their uniqueness as organic reagents and fostered their wide synthetic applications in [3+2] cycloaddition (32CA) reactions to form isoxazolidines, triazoles, carbocycles and other heterocycles of biological and environmental relevance [11][12][13][14][15]. In 2001, Tam and coworkers [16,17] reported the highly regio-and stereoselective intramolecular 32CA reactions of NBD-tethered nitrones and nitrile oxides (Scheme 1).…”