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Ruthenium-catalyzed synthesis cyclization with alkynes

Direct C-H bond functionalization via ruthenium complexes catalysis has been well explored [5]. However, the rapid progress for heterocycle synthesis via ruthenium-catalyzed C-H activation has been only achieved since 2011. By utilizing the less expensive and stable ruthenium(II) complex [RuCl2(/ -cymene)]2, the oxidative cyclization reactions with a series of unsaturated small molecules like alkenes and alkynes proved to be a fast access to heterocycles. Herein, this chapter is intended to provide an overview of reported examples for ruthenium-catalyzed C-H bond activation and cyclization for heterocycle synthesis till the end of 2014, including mechanism presentations... [Pg.187]

Cycloaromatization of enediynes by diradical pathways in the thermal-and metal-catalyzed routes allows nonfunctionalized benzene derivatives to be prepared. The aromatization of enediynes by the action of nucleophiles produces aromatic compounds retaining the respective nucleophilic residue [333, 334]. The ruthenium-catalyzed reaction gives rise to the synthesis of various functionalized benzene derivatives. Thus, adding water, alcohols, aniline, acetylacetone, pyrroles, and dimethyl malonate to acyclic and aromatic enediynes 3.711 at 100°C for 12-24 hours in the presence of TpRuPPh3(MeCN)2PF6 (10 mol%) led to the functionalized benzenes 3.712 in satisfactory yields (Scheme 3.79) [334]. This cyclization involves regioselective nucleophilic attack of enediyne 3.711 to form a, TT-vinylruthenium intermediate 3.714 which finally converts to the benzene derivative. Experiment with labeled hydrogen atoms showed that the ruthenium n-alkyne complexes 3.713 are catalytically active. [Pg.173]

While application of the transition-metal-catalyzed [2 - - 2 - - 2] cycloaddition reaction and its variants for the construction of a benzene unit led to a plethora of natural products with different molecular structures and architectures, its use for the construction of a pyridine moiety within a natural product synthesis is less well developed. The reason for this is uncertain and should not account for the pyridine formation per se the co-cyclization of two alkynes with a nitrile unit to give a pyridine core can be catalyzed efficiently by cobalt, ruthenium, and cationic rhodium complexes, as shown in many methodology-oriented studies [35]. [Pg.226]

By introduction of an oxidizing directing group, Li and Wang demonstrated a regioselective ruthenium(ll)-catalyzed isoquinolone synthesis through oxidative cyclization of JV-methoxybenzamides with internal alkynes (Eq. (7.24)) [31]. This redox-neutral strategy circumvents the use of wasteful metal oxidants, and the reaction could take place at much milder conditions with broad substrate scope. [Pg.206]


See other pages where Ruthenium-catalyzed synthesis cyclization with alkynes is mentioned: [Pg.112]    [Pg.159]    [Pg.260]    [Pg.215]    [Pg.263]    [Pg.260]    [Pg.134]    [Pg.488]    [Pg.646]    [Pg.199]    [Pg.689]    [Pg.492]   
See also in sourсe #XX -- [ Pg.203 , Pg.204 , Pg.205 , Pg.206 , Pg.207 , Pg.208 , Pg.209 , Pg.210 , Pg.211 , Pg.212 , Pg.213 , Pg.214 , Pg.215 , Pg.216 , Pg.217 , Pg.218 ]




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Alkynals, cyclization

Alkynes cyclizations

Alkynes synthesis

Catalyzed Cyclizations

Cyclization alkynes

Cyclization with Alkynes

Cyclizations synthesis

Ruthenium catalyzed

Ruthenium catalyzed cyclizations

Ruthenium catalyzed syntheses

Ruthenium cyclization with alkynes

Ruthenium synthesis

Synthesis cyclization

With alkynes

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