A Tandem Catalytic Approach to Methyleneindenes: Mechanistic Insights intogem-Dibromoolefin Reactivity

Abstract

The methylenindene scaffold can be prepared from readily available gem-dibromoolefins using an efficient palladium-catalyzed tandem intermolecular Suzuki/intramolecular Heck reaction. The reaction is highly modular and proceeds under mild conditions. The choice of ligand was found to be crucial to control the selectivity of the reaction. Isolation of intermediates under different conditions provides insight into the mechanism.

Catalytic 1,2-dihydronaphthalene and E-aryl-diene synthesis via CoIII–Carbene radical and o-quinodimethane intermediates

“…Alternatively, the alkene can also be introduced directly through a Heck-type reaction with 2-bromobenzaldehyde ( Scheme 3 , bottom). 27 Substrates 1a and 1e–l were obtained as pure E -isomers. For the three substrates 1b–d mixtures of the E / Z -isomers were isolated, containing 88–94% of the major E -isomer, which were directly used in the cobalt( ii )-catalysed ring closing-reactions.…”

Reactions of Anodically Generated Methoxystilbene Cation Radicals: The Influence of Ortho-Substituted Vinyl and Formyl Groups

“…(E)-2-(4-Methoxystyryl)benzaldehyde (3). 24 Yellow solid (42.9 mg, 90%); mp 116−118 °C; 1 H NMR (CDCl 3 , 400 MHz): δ 3. 84 (3H,s),6.92 (2H,d,J = 8.8 Hz),7.01 (1H,d,J = 16.2 Hz),7.41 (1H,t,J = 7.8 Hz),7.51 (2H,d,J = 8.8 Hz),7.56 (1H,t,J = 7.8 Hz),7.70 (1H,d,J = 7.8 Hz),7.83 (1H,d,J = 7.8 Hz),7.91 (1H,d,J = 16.2 Hz), 10.33 (1H, s); 13 C{ 1 H} NMR (CDCl 3 , 100 MHz): δ 55.…”

New substituted indene derivatives from bicyclic Baylis-Hillman acetate

“…In addition, indene derivatives are widely used as building blocks for the synthesis of functional materials 14 and metallocene complexes for olefin polymerization 15 . Thus, the importance of indenes has stimulated much interest in the construction of indene system including the ring expansion of suitably substituted cyclopropenes, 16 tandem Friedel Crafts alkylation 17 , [3+2] cycloadditions 18 , C-H bond activation 19 , C-C bond cleavage 20 , thermal cascade reactions 21 , ruthenium-mediated ring-closing metathesis 22 , and skeletal rearrangement using some transition metals and Lewis and Brønsted acid catalysts [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] . However, the above reported approaches suffer from low tolerance of functionality, the use of expensive transition metal catalysts and harsh reaction conditions.…”