Total synthesis of grossularines-1 and -2

Ruthenium(II)‐catalysed Functionalisation of CH Bonds via a Six‐membered Cyclometallate: Monoarylation of Aryl 2‐pyridyl Ketones

“…[2][3][4] The diarylation of ortho CÀH bonds of functional arenes has now become easy to perform with ruthenium(II) catalysts when the formation of a 5-membered ruthenacycle intermediate is possible (I in Scheme 1), [2,3,5] especially with carboxylate-ruthenium catalysts, [6, 7] even in water. [4, 8] The selective monoarylation versus diarylation of functional arenes containing two non-protected ortho sp 2 CÀH bonds, has been shown difficult to achieve via a 5-membered cyclometallate intermediate, [9] unless the [RuCl 2 (PPh 3 )(arene)] catalyst operating in water was used [10] (I in Scheme 1).Compounds containing the aryl 2-pyridyl ketone moiety have shown bioactivity, such as in grossularines [11] and nonplanar b-carboline-based analogues. [12] These unique properties of 2-pyridyl (hetero)aryl ketones and the potential of their derivatives as functional ligands motivate the search for selective aryl CÀH bond activation for further functionalisation, but via a 6-membered metallacycle (II, in Scheme 1).…”

“…Compounds containing the aryl 2-pyridyl ketone moiety have shown bioactivity, such as in grossularines [11] and nonplanar b-carboline-based analogues. [12] These unique properties of 2-pyridyl (hetero)aryl ketones and the potential of their derivatives as functional ligands motivate the search for selective aryl CÀH bond activation for further functionalisation, but via a 6-membered metallacycle (II, in Scheme 1).…”

The Directed Ortho Metallation (DoM)–Cross‐Coupling Nexus. Synthetic Methodology for the Formation of Aryl–Aryl and Aryl–Heteroatom–Aryl Bonds

“…Synthesis of the marine alkaloids grossularines I 159 and II 160[55,154]. is subjected to cross-coupling with the stannylated imidazole 189, obtained by 2-(trimethylsilyl)ethoxymethyl ether-mediated DoM chemistry, to give product 190 in high yields under two catalytic conditions.…”

“…is subjected to cross-coupling with the stannylated imidazole 189, obtained by 2-(trimethylsilyl)ethoxymethyl ether-mediated DoM chemistry, to give product 190 in high yields under two catalytic conditions. Further manipulation including an interesting carbonylative coupling in the final steps, leads in high yields to the antitumor marine natural products 191 and 192[154].An unnamed indolo[2,3-a]carbazole 197, an antiviral and antitumor alkaloid isolated from a blue-green algae, is approached by the Migita-Stille cross-coupling of the 2-bromoindole 193, with the intriguingly stable 2-stannylated N-carboxyindole 194 providing the bisindole derivative 195 in good yields (Scheme 14.38). Sequential treatment with Eschenmoser's salt, MeI, and KCN gives the acetonitrile…”

Biomimetic Synthesis of Grossularines‐1

“…Despite the promising biological activity of 1, only one total synthesis has been completed. [3] In the approach of Hibino and co-workers, the construction of the tetracyclic pyrido [2,3-b]indole ring system proceeded in a linear manner through the use of Pd-catalyzed cross-coupling reactions of halogenated indoles and metallated imidazoles. A formal synthesis of 1 has been reported by Molina et al [4] that intersects the key intermediate reported by Hibino and co-workers.…”