Complex Hydroindoles by an Intramolecular Nitrile-Intercepted Allylic Alkylation Cascade Reaction

Abstract

Bisnucleophilic reagents derived from malononitrile, ketones, benzaldehydes, and nitromethane can react with bisallylic electrophiles via a nitrile-intercepted allylic alkylation cascade reaction to yield complex hydroindole architectures. Also noteworthy is that the only stoichiometric byproducts from the preparation and reaction of the bisnucleophile and biselectrophile are water, acetic acid, and bicarbonate, making it a potentially "green" platform for multistep complex molecule synthesis. These scaffolds can be converted into hydrooxindoles by a unique olefin isomerization followed by Witkop-Winterfeldt-like oxidation.

A divergent procedure for multicomponent synthesis of novel ferrocenyl derivatives of dicyanoanilines and cyanopyridines

“…To support the proposed mechanism, 1a' and 2 0 were synthesized individually via separate Knoevenagel condensations of 3 with 1a and 2, respectively. [37,38] Irradiation of the mixture of 1a' and 2 0 gave 4a, while refluxing a mixture of 1a and 2 0 produced 5a2 (Figure 3). Both control reactions proceeded efficiently in comparable yields and even shorter time periods (4a, 15 min; 5a2, 3 hr).…”

Annulative Allylic Alkylation Reactions between Dual Electrophiles and Dual Nucleophiles: Applications in Complex Molecule Synthesis

“…Interestingly, while intermediate 89 did form as expected, it underwent a facile intramolecular Henry reaction; the resulting enamine 90 then underwent intramolecular allylic alkylation to afford the tricyclic product 92 a in 67 % yield as a roughly 2:1:2 mixture of diastereomers. This unexpected transformation was general and extended to a variety of linker groups ( 92 b , c ), ring sizes ( 92 d ), and side chains ( 92 e ) …”

“…This unexpected transformation was general and extended to av ariety of linker groups (92 b,c), ring sizes (92 d), and side chains (92 e). [32] Heteroatom-heteroatom nucleophiles…”

Stereoselective Synthesis of Fused Vinylcyclopropanes by Intramolecular Tsuji–Trost Cascade Cyclization

“…γ-lactones and γ-lactams. 15 Furthermore, a Tsuji–Trost allylation/retro-Claisen/Tsuji–Trost cyclization sequence was recently reported to afford a range of vinylcyclopropanes. 16 In our strategy, the allylic acetate in 3 is activated by the Pd(0) catalyst, resulting in a 5- exo-trig cyclization in the presence of a base with concomitant migration of the olefin to give 4 ( Scheme 1 , eq 2).…”

“…Previously, the Pd-catalyzed allylic alkylation has proven to be a useful strategy in the synthesis of cyclic compounds, e.g. γ-lactones and γ-lactams . Furthermore, a Tsuji–Trost allylation/retro-Claisen/Tsuji–Trost cyclization sequence was recently reported to afford a range of vinylcyclopropanes .…”