1.3‐Dipolare Cycloadditionen, XXVIII. Diphenylnitrilimin und arylkonjugierte Alkene

Abstract

Styrol liefert ausschfiefllich 1.3.5-Triphenyl-A~-pyralin (2) ; elektronen-liefernde oder -anziehende Kernsubstitution andert die Eindeutigkeit der Orientierung nicht (3 -6). Bei Anethol und p-Isopropyl-styrol werden beide Additionsrichtungen beschritten (7 -10). Dies gilt auch fur P-Methoxy-, P-Brom-und P-Nitro-styrol; die aus der HX-Eliminierung 1580 (1967), vorstehend.

The Nitrilimine–Alkene Cycloaddition Regioselectivity Rationalized by Density Functional Theory Reactivity Indices

“…Finally, RG-III comprises the reactions of diphenylnitrilimine 6 with acrylonitrile (X 1 = CN) [ 20 , 21 ] and several disubstituted ( E )-1,2-ethenes [ 22 , 23 , 24 ] (see Scheme 3 and Table 3 ). All reactions in this group yielded both regioisomers 7 and 8 spanning a largely different product ratio.…”

Biomedical applications of copper-free click chemistry: in vitro, in vivo, and ex vivo

“…Furthermore, the nitrilimine produced by photoexcitation of diaryltetrazole is highly reactive, so that the reaction rate is very fast (k $ 60 M À1 s À1 ). 33 A recent study of the Wagenknecht group used this reaction for facile labelling of DNA using cyanine dye showing the utility of the photoclick reaction. 34 However, the wavelength of light used in photoclick reactions is generally in the ultraviolet (UV) range, which is a limitation in biomedical research.…”

Bioorthogonal Ligations and Cleavages in Chemical Biology

“…They found that the smaller substituents facilitated the decaging process, and the tetrazines containing EWG group and small non-EWG group at the 3-and 6-position showed the remarkably enhanced decaging rates to lead to the protein activation in living cells. [143] Weissleder and co-workers investigated the corresponding mechanism and found that acid-functionalized tetrazine (153) could markedly accelerate release and ultimately uncover an unexpected dead-end isomer (156) for poor release. N-Methyl derivative 157 could prevent formation of this dead end and achieve exceptional efficiency ( Figure 32).…”