Palladium‐Catalyzed Formation of Highly Substituted Naphthalenes from Arene and Alkyne Hydrocarbons

Abstract

Several highly substituted naphthalenes 3 have been synthesized in a one-pot reaction by treatment of arenes 1 with alkynes 2 in the presence of palladium acetate and silver acetate. In this Pd-catalyzed protocol, an arene provides a benzo source for the construction of a naphthalene core through twofold aryl C-H bond activation. Reaction of triphenylphosphine with diphenylethyne (2 a) under the catalysis of Pd(IV) complexes produced 1,2,3,4-tetraphenylnaphthalene (3 ba) in 62 % yield. Here, triphenylphosphine undergoes one aryl C-P bond cleavage and one aryl C-H bond activation to serve as a benzo moiety. Crystal structures of cycloadducts 3 ea, 3 ga, and 3 ac have been analyzed. The twisted naphthalenes arise not only from the overcrowded substituents but also from the contribution of the CH(3)-pi interaction.

Synthesis, Structure, and Photophysical Properties of Dibenzo[de,mn]naphthacenes

“…Communications be 4,5,6,11,12,13-hexahydrozethrene (9 a, R = H), which was verified by X-ray crystal analysis. [19] In addition, 9 a was predicated to be the final hydrogenation product of zethrene (1 a) almost 60 years ago.…”

Dehydrogenative Heck Annelations of Internal Alkynes

“…With 2-aryl-1-methylindole (Equation 16), 3-aryl-1-methylindole (Equation 17) or 2,2′-bis(N-methylindolyl) (Equation 18) as the substrate, the DHA implies one molecule of the alkyne. 36 After screening of different parameters, Jiao and co-workers performed these domino reactions in N,N-dimethylformamide, as above in the presence of an organic acid, but with addition of substoichiometric amounts of both tetrabutylammonium bromide and potassium carbonate.…”

“…18 The catalyst regeneration was assumed by silver acetate, and was favored by the presence of oxygen since the reaction time decreased under an air atmosphere instead of nitrogen. A large excess of the arene was used for these syntheses, yields were modest and a mixture of isomers can be produced (Equation 7).…”

π-Conjugated carbocycles and heterocycles via annulation through C-H and X-Y activation across CC triple bonds

“…Also, the catalysts are useful for the annulation between 77 and diphenylacetylene, and between 79 and alkynes, to give the annulation products 78 and 80, respectively. 116,117 Recently, our group reported Rh(III)-catalyzed regioselective annulation between naphthylen-1-ylcarbamates and alkynes (RC≡CR); Intramolecular annulation between alkynes and arenes of 81, in which EWG group was substituted, via C-H activation was catalyzed by Pd(OAc) 2 /d-i-Prpf (1,1′-bis(diisopropylphosphino)ferrocene) system, giving fluorene derivatives 82 in very high cis-selectivity (Scheme 25). 119 The C-H activation takes place at EWG substituted benzene (as shown in 83), and following carbopalladation gives 84.…”